PART II

EVERYDAY MACHINES

I

SOME PRACTICAL ADVICE

Some of our inventions and some of our discoveries are of comparatively recent date, but most of them had their beginnings centuries before historical times, as many of our greatest inventions are the result of gradual growth and development. The early discovery, by some unknown persons or persons, of the making of bronze and the hardening of it, led up to stone and woodcutting, perhaps to the breaking-up and smelting of iron ore, and the extraction of the metals. This again opened the way for the making of steel, a discovery that placed in the hands of man a source of power which enabled him to overcome many natural difficulties. One improvement led the way to another, and made other improvements possible. Take locomotives and steamboats for instance. The making of a raft, no doubt, suggested the canoe, and this led to the built-up boat, and the ship. The paddle and the oar doubtless led up to the sidewheeler, and the scull to the propeller. The crude steam engine of Hero very likely suggested the steam engines now in use, and this new power rendered it easy for Stephenson and Fulton to perform their work; but, if either of these inventors were to come back to the earth and examine the great steamers of to-day, or the perfect and powerful locomotives now in use, they would be surprised to think that the present tractable monsters, were the outgrowth of their early efforts.

In the same manner may be traced the same gradual growth in all the arts and sciences; for step by step, in every department of life, have completeness and perfection come to us. It is not yet one hundred years since Congreve invented or rather completed the invention of the "Parlor match," called in his day, the "Lucifer match." This grand achievement was accomplished after many failures in the efforts of chemists for ages. The perfection of the match was a great blessing to humanity, as the old methods of making a light or fire were tiresome and very uncertain. So it is with many of the blessings we enjoy to-day: they are simply the results of the struggles of many unknown minds, the threads of which were gathered up and pieced together by one master mind, so as to be made useful and profitable to mankind.

In the early and middle ages, the inventor was looked upon as a wizard, a sort of inferior demon, or, at best, an uncanny kind of man, and a proper subject for the stake. When, by superior wisdom and skill, he invented some machine or device, or discovered some new and better method of accomplishing a useful end, he was at once looked upon as a necromancer in league with his Satanic majesty, and, therefore, unfit to associate with or be recognized as a Christian. History records many instances of inventors and progressive men being persecuted--and executed--because of their having discovered or invented something which would interfere with some vested or imaginary rights. The new inventions must be destroyed or put away out of sight and hearing, and the most powerful influences were employed to bring about this result. The stories told of Friar Bacon, Papin, Crompton, and hundreds of other inventors, give us a few of the reasons why so little progress was made in the arts and sciences previous to the sixteenth century.

Down to a period within the past few years the term invention has been considered almost synonymous with the word chance. An inventor, was a lucky individual, who had happened to hit upon some new idea, not so much by his own great ability as by good fortune, similar to that which brings success to the purchaser of a lottery ticket.

In many cases this was really the true state of affairs. Men who experimented in various mechanical pursuits often stumbled upon results, which they perceived to be useful and valuable, and, if they protected the invention by patent, they often became wealthy.

At the present time this meaning of the word invention must be greatly modified, if not altogether abandoned. The law which controls the action of the forces of nature is becoming so well understood among all classes of mechanics that chance invention, in the early sense of the term, has almost become an impossibility. Success can be assured only to the man who has tried to win it by the acquirement of the necessary knowledge, to be obtained by steady application and hard study. In the pursuit of discovery, the old saying, "knowledge is power," never has had more force than when applied to unravelling the tangled web of nature's mysteries. "Science," says Lord Brougham, "is knowledge reduced to a system."

A man may have a lifetime of practical experience and amass a fund of knowledge of great use to himself, but entirely unavailable for others. But if his experience be combined with that of other men and systematized into a regular order, it becomes part of the science of that branch of industry, and although the person himself may have a profound contempt for science and theory his work may be quite scientific.

Ignorance, in the past centuries, was another great factor in preventing mechanical progress. New machines and labour-saving devices were looked upon by the great mass of workers as contrivances designed to deprive them of the means of making an honest livelihood, and this point of view caused the people to smash and burn many machines that had cost great labour and expense to the unfortunate inventor. But, as public schools became more numerous and learning increased, the way of the inventor became smoother. The more enlightened nations encouraged inventors and inventions, and now our country has on its statute books laws for this purpose, the most liberal in the world.

The opportunities for obtaining mechanical and scientific knowledge and technical instruction are now so many and so easy of access that inventors have but little trouble in acquiring the data and facts essential to their purposes. The earliest students had nothing but their own observations and experiences to build on, and even as late as the eighteenth century, men had to grope in the dark for the data required to carry out their ideas. A brief examination of the early treatises on mechanics and the rude illustrations in the works of Leopold, Amoutons, and Desaguliers will reveal the germs of many modern machines.

The inventor of to-day, however, must proceed by a different path from his predecessor, if he expects to succeed in the present advanced state of mechanical arts. The demonstration of the mechanical equivalent of heat, the discovery of the correlation of the physical forces, and the development of the sciences of thermo-dynamics have furnished powerful weapons for the advancement of mechanical science, and he who does not use them is at a woeful disadvantage in the fight. There is no "royal road" to success for the inventor, and I hope you will always bear this in mind when attending to your studies, for you must remember that it is nearly always necessary to use formulæ and symbols to express relations, which are hardly within the range of words, and often a combination of data obtained from different sources may be used to derive entirely new relations.

It is here that invention, in the modern sense of the term, comes in to hold a place midway between theory and practice, and may be properly called a science.

THE LAWS OF GRAVITATION

Suppose a one-pound weight is suspended by a string: there is a tensile stress in the string, varying slightly at different parts of the earth, but always the same at the same place, say, Newark, for the variation is very slight within a pretty wide area. If we take a spring balance and graduate it in pounds at Newark, such a balance will accurately indicate forces in pounds wherever it may be used. The stress produced in a string carrying a one-pound weight at Newark is the unit of force. If the string with its weight is hung from a nail, the nail is pressed on its upper side with a force of one pound. The same pressure may be produced by pushing the nail downwards from above, using a short piece of stick; in such circumstances, the stick bears a compression stress of one pound. This is a good, common-sense definition of force, though it does not by any means cover the whole subject. The word force is used in a different sense by persons who speak of the force of gravity. When a one-pound weight is suspended by a string, as stated in the foregoing, the attraction between the mass of the weight and the mass of the earth is balanced by the stress in the string. We can double the stress by doubling the weight, and in this way, by adding weights, we can make the force of gravity very great. But the force of gravity is spoken of as an invariable thing, and it is said to be equal to 32 (roughly). If any weight whatever be allowed to fall freely (for reasonable heights and neglecting the effect of the resistance of the air) it will be found that at the end of the first second it will have a velocity of 32 feet per second; at the end of the second second it will have a velocity of 64 feet per second; and generally at the end of any number of seconds its velocity will be 32, and the rate of increase of velocity (acceleration) is 32 feet per second, all of which has been previously explained. It is found convenient to call this acceleration gravity--it is inaccurately called the force of gravity, it varies at different places on the earth. It is usual to designate the acceleration by the letter g, and we speak of the g, or gravity, of the place. This seems to cover the point of inquiry completely.

The subject of specific gravity is a far-reaching one, and includes the testing of liquors for revenue purposes and many other things of a scientific nature; but when we speak of specific gravity in an ordinary way we mean the comparative weight, bulk for bulk, of water at a certain temperature. The specific gravity of a substance like coal can be ascertained experimentally. By means of a specially adapted and delicate balance, the sample of coal is first weighed in the ordinary way, after which it must be weighed suspended in a vessel of water. Weighed in water, it will be found the coal does not weigh so much. If the loss of weight, or the difference between the first and second weighings be taken, and the first weighing divided by this loss of weight, we obtain the specific gravity of coal. For example, suppose a sample of coal weighs in the ordinary way 20 ounces, and in the water only four ounces, showing a loss of weight of 16 ounces. Divide 20 by 16, and we get the specific gravity of the sample of coal, viz., 1.25.

The use of specific gravity is of great importance in mining, with regard to analysis of the minerals worked, for with a class of coal having the same relative composition, qualities, and calorific power per ton of coal employed for different purposes, yet having a higher specific gravity, the room required for storage or transport will be less. This is an important factor, where there is limited space, as in depots and naval vessels. It is also employed in the arts and industries for many purposes, and is particularly useful to workers in precious metals, as the amount of alloy or baser metal may be determined by it that have been used in the manufacture of jewellery, plate, and similar articles.

To put it briefly: Specific gravity is the ratio of the heaviness of any substance to that of water. The specific gravity of water is taken as unity, and that of any other substance is expressed as a decimal. Tables of the weight and specific gravity of substances can be found in any good hand-book of engineering.

HOW TO ADJUST SEWING MACHINES.

Sewing machines often get out of order, and it is not always that an expert is at hand to adjust them, so a few general observations on the subject of these household machines may prove useful and interesting to every one who is at all mechanically inclined.

There are several distinct types of machines, but we shall confine our remarks to the Singer vibrating shuttle, the hook shuttle types, and one or two others. To secure a perfect stitch in the vibrating shuttle machine, and to keep it from puckering thin goods, such as Japanese silks, muslins, and voiles, though possible, is difficult. Success depends entirely on the careful fitting of parts and the skilful adjustment of the machine to the particular fabric. In the first place, it is essential that a machine should work quite freely, a point not of such great importance if it is used for rougher classes of work.

Machines used for domestic purposes, like the V. S. (vibrating shuttle), often stand unused for weeks together, so that the oil thickens and makes a machine run somewhat heavily and unevenly. This may indirectly affect the regularity of the tension, especially with thin goods. Therefore, it is important to keep a machine clean and regularly oiled. Important parts are often overlooked during the operation; in fact, many users of machines do not know how nor where to oil one properly. Therefore Figs. 79 and 80 will be helpful, as they show the location of oil holes and parts to be oiled, and the illustrations will serve as a guide to other machines. In these figures, it will be seen that there are a number of parts to oil which could very easily be overlooked. When a machine has been unworked for a length of time, the application of a little paraffin will cleanse the parts which should afterwards be oiled thoroughly with a good quality of machine oil. The shuttle raceway, where the shuttle works, should be wiped out with an oily rag. Any lint or dirt which has accumulated inside the shuttle at the nose end should be withdrawn, as such might retard the unwinding of the bobbin. It is imperative that the cotton should pull evenly, that is, free from jerks; this refers to the upper as well as to the lower tension.

For silk and similar materials, best results can be obtained if fine cottons are used. Numbers 60, 70, or 80 would be preferable to No. 40. A good quality of fine silk is even better. It must be remembered that when working on thin silk, say two thicknesses, a coarse cotton cannot be locked centrally. Fine cotton will need a fine needle, which necessitates a fine hole needle plate.

If, after the foregoing points have been attended to, the machine runs easily, the parts fit properly, there is no end play to the upper shaft and the cottons pull evenly, yet the tensions are erratic, attention should be given to the loop as it draws off the shuttle heel. In machines of the C. B., O. S., and especially the V. S. class, there is a tendency for the loop to hang on the heel of the carrier, or to become trapped between the shuttle and the carrier heel. In the two former types of machines, the heel of the carrier should be rounded so as to induce the cotton to pass off as freely as possible. Sometimes it is necessary to time the shuttle a little later, that is, put the carrier back a little to allow the loop to draw off more in a line with the hole in the needle plate.

In V. S. machines the carrier is already rounded off at the heel. By referring to Fig. 80, the action of the shuttle in the raceway can be seen, which is from A to B. The shuttle, having just entered the loop, is about to move to B. This movement can be regulated by an eccentric screw and nut (Fig. 80). When a machine has been taken to pieces and cleaned, this screw is not always replaced to the best advantage. If the shuttle moves too much toward B, the loop is carried by the heel of the carrier, and, at the same time, the shuttle cotton, by bearing tightly on the needle plate, pulls the shuttle toward the carrier heel, thus making it difficult for the loop to release itself. More tension is applied, perhaps more pressure is put on the take-up spring, yet the uneven tension is not overcome, and owing to the softness of the fabric, it is drawn up or puckered. The remedy is to turn the screw C (Fig. 80), until the carrier is in a position to allow the loop a free exit.

For such soft materials as mentioned it may be necessary to slacken both tensions. It should be remembered that the upper tension is generally somewhat tighter than the under one, and this should be a guide to the adjustment of the latter, according to the fabrics to be stitched.

To prevent puckering when the tensions are correct, reduce the pressure of the foot by loosening the thumbscrew D (Fig. 79). Use a small size stitch--set the feed so that the teeth are just above the needle plate. Do not have the teeth too sharp, and if necessary, rub off the knife edge with F emery-cloth. Make the foot to bear squarely on the needle plate, and the feed square to the presser foot. Round off all sharp edges from the under side of the foot, especially the back edge. Special feeders are made for silk goods in machines used for factory work, which overcome the difficulty of puckering.

By attention to the foregoing instructions, a machine should work easily, especially if the fabric is slightly pulled from behind the pressure foot.

In C. B. machines, attention should also be given to the loop as it passes over the bobbin case and off the stop pin, it being necessary sometimes to round off the latter. If the tension spring screw projects too high or is rough, it may occasionally catch the cotton.

The machine shown at Fig. 81 is of the "Rotary Hook"--zigzag type. Its uses are similar to that of the oscillating shuttle type, but its construction is rather more complicated.

The machine may be said to consist chiefly of an upper and a lower shaft, each having two cranks. In the vertical portion of the arm are two links which connect the shafts, causing them to work in unison with each other. The upper shaft gives motion by means of a cam and link to the needle bar and take-up lever; while the lower shaft, by means of three gear wheels, gives the rotary movement to the hook or shuttle, and by an eccentric cam and segment lever the necessary motion is given to the feed or stitch mechanism. Figure 82 shows the rocking frame into which the needle bar is fitted at A and B, while, at C and D, it is recessed to receive the taper ends of two screws, which pass through the face plate end of the machine arm. These screws are held secure by lock nuts, so screwed in as to allow the frame to rock freely. A ball-headed screw is fitted at E, to which is fastened a connection rod extending to a switch lever situated about the centre of the arm. This lever, by means of a cam movement, gives the vibrating motion to the needle bar, which can be regulated according to the relative position of the connection rod and lever. When the rod is at the bottom of the lever, a wide throw is obtained. By raising the rod a narrower throw is given, and if raised to the position shown in Fig. 81 no vibration will be given to the needle bar. The needle bar can be raised or lowered by loosening the screw that secures it to its link collar, which will be better seen by removing the face plate. Most needle bars have two marks upon them, and they should be set as follows: Remove the face plate, and turn the hand wheel F (Fig. 81) toward you until the needle bar link has reached its lowest point of travel.

Loosen the set screw of the needle bar collar, and set the needle bar so that its highest mark will be just level with the bottom of the rocking frame (Fig. 82). Then tighten the set screw, give the hand wheel a spin round, and again examine the position of the mark when the needle bar has reached its lowest point of travel, to make sure that no mistake has been made. Of course, it is necessary when parts are badly worn to set the needle bar a trifle lower, but this can be done after the foregoing rule has been adopted and proved a failure. In case of any unnecessary looseness in the middle bar or any of its connecting parts, they should be taken out and new parts fitted. The position of the needle may be altered to the right or left by loosening the screws G and H (Fig. 81), and adjusting the connection rod. Care should be taken not to set the connection rod too low down, or the needle may strike on the needle plate and cause trouble.

Fig. 83 shows the face plate removed from the machine arm, A being a tension release lever. When the presser foot is lifted to its highest position, the end of the lever goes between the tension disc, thus releasing all tension, so that materials can be taken from the machine without drawing slack cotton, or putting any unnecessary strain on the needle. When the presser foot is lowered, this lever should withdraw itself from the disc, thus allowing the proper tension to be put on the cotton. In some machines the withdrawal of this lever depends on a stud screw, fastened to the needle bar and projecting through the face plate. In the downward course of the needle bar this stud screw touches a spring, and causes the lever to trip backward. Should the spring become strained, or the stud screw become raised up a little, the release lever may remain between the disc and cause trouble. Sometimes it is necessary to bend the lever forward or backward to ensure its proper action.

The hook or shuttle is rotary in motion. The hook (Fig. 84), is fitted to a ring, which is fixed to the hook guide (Fig. 85) by means of three small pins, and it is prevented from falling out by a steel cap secured with two screws and springs. The hook is carried round by a driver (Fig. 86). Much depends on the hook, driver, and hook guide, so that a little detailed information is necessary. The hook driver must be a perfect fit in its bearings and free from sharp places where it comes in contact with the hook. The body of this driver is generally hardened, but the prong J (Fig. 86) is left soft so that it can be bent to meet requirements. When a machine is stitching, the hook driver rotates, and the prong J draws a given amount of slack cotton from the bobbin case. The farther this prong stands out, the more slack cotton it draws off the bobbin. The prong may be bent inward, as shown by the dotted lines, but care must be taken not to drive it in so far as to allow the needle when descending, to strike on it, or to deviate from its true vertical position. Points K and L fit between the nose and neck of the hook, while M comes against the heel. The hook is driven alternately by points K and M. When the hook is just entering the loop formed by the needle, it (the hook) is being driven by the driver wheel or M, and an opening is being made between point K and the hook nose for the free passage of the cotton. When the loop is being drawn off the hook by the take-up lever, the hook is driven by point K, and an opening is made between M and the heel of the hook for the exit of the cotton. There must always be sufficient clearance at points K, L, and M for the cotton or thread being used. As the heel of the driver M wears, the space at K will be reduced. Sometimes this can be remedied by bending the driver in at M, by giving it a blow with a hammer, placing a brass punch at M, but this should not be attempted if the driver is very hard. There is a means of adjustment provided in the hook guide (Fig. 85). This part is held in position by two set screws N and O. At the left of O is a small adjusting screw P. Supposing there is not sufficient space at point K (Fig. 86), for the cotton to pass, loosen the screw O (Fig. 85), and slightly tighten the screw P. This will tilt the hook guide and give more space. Should the screw P be turned in too far, the point L (Fig. 86), will be brought in contact with the narrow part of the hook near the neck, and this will impede its freedom, so that if allowed to run at much speed, the probable result will be the breaking of the hook off at the neck. This should be noticed in fitting a new hook, as the adjusting screw P (Fig. 85) will in all probability require loosening. The screws at N and O, however, must be kept quite tight. At each side of N is a small screw hole. The screws which fit here are for adjusting the hook closer to or farther from the needle. As an example, supposing a very fine needle has been used in the machine, and it is now required to take a very coarse one on account of the thick material to be stitched, the hook in all probability would strike the needle, indicating that the hook guide requires moving back a little. To do this, loosen the two small adjusting screws and tighten the set screw in N. Afterward try the set screw in O to ascertain if it is secure. In this way, the hook is thrown farther from the needle. Loosening the screw at N, and tightening the adjusting screws, will bring the hook forward. If the hook stands too far from the needle, it is likely to miss the loop. The hook nose must be well pointed and perfectly smooth, roughness or sharpness removed from any part of the hook over which the cotton passes during the formation of a stitch.

Hook rings are made in three sizes, numbers 1, 2, and 3. Number 1 is for a new hook, numbers 2 and 3 are for fitting as the hook wears. No matter what size of ring is used the hook must have perfect freedom. Sometimes the three pins in the guide draw the ring, and cause the hook to bind. It is best, therefore, to fix the ring to the guide, and then test the hook. If it is at all tight, grind it on the rim by means of an emery wheel or a grindstone. If neither is available, use number 1 or number 1-1/2 emery cloth first, finishing with number 00 emery cloth. It is better to have the hook a little loose, even sluggish, than too tight. The timing of the hook will be dealt with later on.

The bobbin case (Fig. 87), fixes to a stud in the centre of the hook. It is held in position, that is, kept from revolving with the hook, by means of a stop pin, Q, fitting between a holder. The tension is obtained by a spring, R, which is regulated by turning a small screw, S, to the right to tighten and to the left to loosen. Fig. 88 shows the bobbin case in position, with the holder raised ready for taking it out of the machine. Fig. 89 shows the bobbin in position in the bobbin case and method of threading, and Fig. 91, the direction the cotton should draw off the bobbin when it is in the machine. It will be noticed that the cotton pulls in the opposite direction to which the hook travels, as shown by an arrow in Fig. 88. The bobbin case holder (Fig. 91), should prevent the bobbin case from revolving with the hook. As parts wear, the bobbin case is liable to slip past the holder, causing the cotton to be stranded and broken. When such is the case the holder should be bent as shown by (Fig. 92), but it must not fit so tightly against the bobbin case as to cause the cotton to become trapped. The holder is held rigid by means of a catch and spring T (Fig. 88). Should the catch or holder become worn, fit new parts by driving out the pins U and V. Any sharpness or roughness on the forked part of the holder should be removed. Should the stop pin Q (Fig. 87) become loose, it should be soldered and well cleaned with an emery cloth. The centre tube of the bobbin case should also be kept quite firm. Should it become loose, place it over some hard substance, rivet it until tight, and thoroughly smooth with very fine emery cloth.

The take-up spring (Fig. 93) is attached to the face plate, and is shown in position in Fig. 83. Replace a new one as follows: First take out the set screw W (Fig. 93), and remove the complete thread controller from the face plate. Then take out the screw and withdraw the old spring. Place the ring part of the new spring in the recess between plate Y and back plate Z, and replace the screw X, being careful not to get the spring fastened under the screw head. This done, fix the spring and other parts on the face plate. A small barrel with a slot in it receives the coiled portion of the spring. See that the part of the spring that is turned in enters the slot in the barrel, then replace the screw W, but before tightening this screw, see that the hooked part of the spring A´ rests on the regulator B´, which determines the amount of action given to the take-up spring. By raising it, less action is given. The amount of pressure on the spring is regulated by adjusting the barrel in the face plate. Take off the face plate, loosen the screw C (Fig. 83), fix a screw-driver in the rear of the barrel (seen inside the face plate), turn it toward you for more pressure, and backward for less and tighten the set screw C.

Presser feet are made solid for ordinary purposes, although alternating feet can be fitted when desired. Figs. 94, 95, and 96 show a pressure foot, collar, and spring. To fix this foot, remove the ordinary presser foot, turn the foot bar round by loosening the set screw, so that the groove made for the reception of the presser foot is directly behind the needle. Put on the collar (Fig. 95), then turn the foot (Fig. 94), and screw it in position. Next place the spring each side at the points D´ (Fig. 94), press down the collar (Fig. 95), and secure it by its set screw. The springs will act on each half of the foot, and keep them firm, though the material be uneven. The foot is particularly useful when overseaming a hem or the top band of a lady's boot, etc. To time the hook and needle, raise the connection rod so as to produce no throw, and tighten the screw as in Fig. 81. Then take off the needle plate and remove the slide E´ (Fig. 81) under which will be seen a crank and screws.

Now turn the machine back as at Fig. 88, lift up the bobbin case holder by pressing the catch T, and remove the bobbin case. Take off the hook guide cap by removing the two screws. Turn the hand wheel F (Fig. 81), toward you, until the needle bar has descended to its lowest point of travel, and loosen the crank screw farthest from you. Having done this, continue turning the hand wheel until the needle bar has risen. With the lowest mark level with the rocking frame casting, at this point, examine the hook, the point of which should be just up to the needle. If otherwise, loosen the other screw in the crank under the plate E´ (Fig. 81). Be sure the needle bar mark is level with the rocking frame, place the hook with its point just up to the needle, and tighten the crank set screw, being careful to have no end play to the short shaft. Again examine the needle bar and hook and if in proper time finally secure crank set screws and replace the fittings previously removed. Thread the machine as indicated (Fig. 81). Set the needle as high in the bar as it will go, with the long groove facing the operator, and thread the needle from the long groove side. The stitch regulator will be found at F´ (Fig. 81). The raising of it will shorten and the lowering of it will lengthen the stitch. The feed should be set about one thirty-second of an inch above the needle plate when at its highest point. To raise the feed, turn the machine back as in Fig. 88. Near to the part G (Fig. 88) will be found a large set screw. Loosen it and press the lever H (Fig. 88) upward raising the feed bar J as high as required, and tighten the set screw at G firmly. To remove the feed for cleaning and sharpening, take off the needle plate, under which will be seen two feed set screws. By unscrewing these, the feed can be lifted out.

One of the modern machines on the market is the Wheeler and Wilson, known as the Number 61, which is of rotary hook principle. The hook forms part of the under shaft, somewhat similar to that known as the D9 W and W. This hook and shaft revolves in two long bearings, and is held in position by a fluted wheel, which forms a collar at the right-hand end; thus when set properly no end play is permitted. This is an advantage over the boat-shaped shuttle machine. In the latter, the shuttle rocks about, becomes worn on the surface, often blunt pointed by striking the needle. As it wears, it becomes loose in the carrier, thus giving it freedom to roll away from or toward the needle, as well as making its action with relation to the needle very uncertain; and on account of the number of little loosenesses in fittings that this uncontrolled shuttle produces, missed stitches are frequent, and difficult to remedy, unless a number of new fittings are obtained or old ones repaired.

If there is any alteration required in the time of the rotary hook referred to, it can be made to the smallest fractional part of an inch very quickly and easily, and the movement can be relied on. The shaft to which it is secured is positive in its action (no variable motion), and at every stitch will meet the needle at exactly the same spot. This is an improvement over the boat-shaped shuttle, which has to have a certain amount of play or slackness to allow the loop to extricate itself; and this slackness increases as the machine is worked, so that the shuttle action often becomes very erratic.

Sometimes a carrier becomes sprained at one end, thus allowing the shuttle too much freedom. If at the heel end, the carrier should be removed and placed in a vise (heel uppermost). The heel should be given a light blow with a hammer, thus bending it into correct position, but it must never be allowed to incline toward the shuttle; it should stand perfectly square, and have the upper corners rounded off. If inclined toward the shuttle, the loop may occasionally hang on the heel, and cause an irregular tension.

In some machines the bobbin case holder (Fig. 97) rests on the casting seen in Fig. 81. It is secured by a large set screw, D (Fig. 97). For general use, this screw should be adjusted to allow number 40 cotton to pass freely over the bobbin case. The holder should not be removed, except when adjustment or repair is needed. The vertical portion is hinged to the base, and is kept upright by a lock spring and stud. If the spring is pressed from the stud, the vertical or ring part can be drawn back for placing in or taking out the bobbin case. The face of this portion must be perfectly square with the bottom of the base, otherwise it may cause considerable trouble. A slight adjustment can be made by loosening the two screws and moving the lock spring. A set square, E, should be used for testing the accuracy of this part as shown (Fig. 98), F representing the bobbin case holder.

The thread controller is similar in design to several others, but its movement is regulated by a small lever (Fig. 99) which receives its motion from a link attached to the foot bar bracket set screw, and this may be seen through a hole in the face plate. At G (Fig. 99), this lever engages with a stop washer located behind the thread controller plate. The washer is recessed to form a stop, at the same time to give sufficient clearance for the action of the spring; thus as the foot bar rises and falls, so does the thread controller spring. It is a common practice when cleaning a machine to remove the face plate, thus detaching the link referred to, and not connecting it again when replacing the face plate. From this, trouble arises. The tension pulley should be placed on its stud, the large boss being toward the face plate.

Thread a machine as follows: From the reel pin to nipper F (Fig. 81), round tension pulley G as the arrow indicates, down and into thread controller H up to take-up lever, threading over the roll and through the slot from the top of lever, then down the thread guide J, into guide K, and through the needle-eye from right to left.

In the ordinary boat-shaped shuttle, the looping up of the thread is not difficult. The needle, as it descends, enters an opening or cavity in the carrier, one side of which forms a support for the needle and guards it from contact with the shuttle point. Now, it is important that there be clearance for the needle. If the carrier stands so prominent as to spring the needle out of its true vertical line it will carry it away from the shuttle, and give the latter a chance to miss the loop.

Then there are carriers and drivers of varying heights. Those of the raised kind are preferable, if properly fitted. By "raised" is meant that they are higher, so as to form a better guard for the needle, as previously referred to (Fig. 100 A, in which E indicates the portion of raised carrier, F the shuttle point, and G the needle). But sometimes they are too high, and permit the needle-eye to be buried in the carrier, thus preventing the proper formation of the loop. This can be so bad as to cause very frequent missing; or it may be of such a slight character as to cause a miss-stitch only now and then. Occasionally, a needle bar has to be lowered, and that is sufficient to cause the same fault. The eye of the needle should always be about one thirty-second of an inch above the upper edge of the carrier, and the latter should be shaped so as to allow that amount of clearance the whole of the time the needle is rising to form the loop, until the shuttle point has well entered the same. Fig. 100 B shows how a carrier is hollowed to give the necessary clearance to the needle eye.

When a machine is reasonably tight in all parts, gauges and setting marks may be adhered to for the preliminary adjustments; and then if the machine works erratically, other adjustments must be made. Where no marks or gauges are furnished for the adjustment of the needle bar, it should be so set as to allow the shuttle or hook to enter the bold part of the loop formed from the needle. A good rule is to set the needle bar so that the needle-eye is about 1/32 inch below the point of the shuttle M (Fig. 100 C) when the latter is up to the centre of the needle groove. But this may have to be varied from 1/64-inch to 3/32-inch. In boat-shaped and similar shuttle machines, a good rule is to set the needle so that the eye N will pass just below the lower side of the shuttle O as the latter is passing through the loop as in Fig. 100 D, P, indicating the level of the bed plate.

II

MECHANICAL MOVEMENTS

What is meant by this term is that these devices are intended for the transmission of motion. Motion in mechanics may be simple or compound. Simple motions are those of straight translation, which if of indefinite duration must be reciprocating, or what is called oscillating or helical.

Compound motions consist of combinations of any of the simple motions. Perpetual motion is an incessant motion conceived to be attainable by a machine supplying its own motive forces independently of any action from without, or which has within itself the means, when once set in motion, of continuing its motion perpetually, or until worn out, without any new application of external force. The machine by means of which it has been attempted, or supposed possible to produce such motion, is an invention much sought after, but physically impossible.

The illustrations herewith exhibit a number of devices of various kinds, well known to the practical mechanician and professional engineer, and usually called mechanical movements. It is estimated there are no less than 1,500 of these movements doing service at the present day; but many of them are, of course, quite complex, and difficult to master. In this book, I show about one hundred of the simplest sort, or those in common use. Their usefulness will at once be appreciated if we refer to Fig. 102, which shows a machine for grinding or breaking up substances within its capacity. It contains within itself the true principle of the little mill used to grind coffee. The word "grind" in this connection is scarcely the right one, as the mill rather "crushes" or breaks up, than grinds. You will notice coffee, ready for use, is coarse and unlike flour in texture, the latter being "ground" fine and smooth. In grinding, the abrading surfaces are brought very much closer together than in the breaking or crushing processes. In a coffee mill, the berries or grains drop into a vacancy, left between the revolving cone and the walls of the mill. The vacancy between the walls and the cone is a little less at the bottom where the crushed coffee is discharged, and this enables the small and large grounds to fall into the drawer. The detailed plan in illustration (Fig. 102) shows a mill complete, as well as the various parts. It will be noticed that the cone (Fig. 5), is corrugated or grooved as shown (Fig. 4). Figs. 6 and 7 show sections of lining at B and C (Fig. 3). A shows the hopper into which the coffee berries are placed before grinding. Figure 9 shows the crank detached, and Figs. 8 and 10 show the remaining parts of the machine, while Figs. 1 and 2 show the handle and drawer. The latter is to receive the ground or crushed coffee after it has gone through the mill. Further description is unnecessary if we take for example the movement represented at Fig. 150, which is a sort of ball-bearing motion, only instead of small balls wheels are used. Besides being made use of in bicycles in small balls, it is used as depicted for "hanging" grindstones, and for many other similar purposes.

The device also shown at Fig. 139, is one in common use. It is a modification of the sprocket wheel on the bicycle. Many of the devices shown herewith are rarely noticed because of our familiarity with them.

The action of pumps, the working of pistons, the changing of motion, and many other things are shown and explained in the little illustrations given in these descriptions, which do not pretend to be exhaustive, or even full.

Fig. 103. In this the lower pulley is movable. One end of the rope being fixed, the other has to move twice as fast as the weight, and a corresponding gain of power is consequently effected.

Fig. 104 is a simple pulley used for lifting weights. In this the power must be equal to the weight to obtain equilibrium.

Fig. 105. Blocks and tackle. The power obtained by this contrivance is calculated as follows: Divide the weight by double the number of pulleys in the lower block; the quotient is the power required to balance the weight.

Fig. 106 represents what are known as "White's pulleys", which can be made with separate loose pulley; or a series of grooves can be cut in a solid block, the diameters being made in proportion to the speed of the rope; that is, 1, 3, and 5 for one block, and 2, 4, and 6 for the other. Power as 1 to 7.

Figs. 107-108 are what are known as Spanish bartons.

Fig. 108 is a combination of two fixed and one movable pulley.

Figs. 111-113 are different arrangements of pulleys. The following rule applies to these: In a system of pulleys where each is embraced by a cord attached to one end of a fixed point, and at the other to the centre of the movable pulley, the effect of the whole will be the number 2 multiplied by itself as many times as there are movable pulleys in the system.

Fig. 114. Endless chain for maintaining power on going barrel, to keep a clock going while winding, as during that operation the action of the weight or mainspring is taken off the barrel. The wheel to the right is the going wheel, and that to the left the striking wheel. P is a pulley fixed to the great wheel of the going part, and roughened to prevent a rope or chain hung over it from slipping. A similar pulley rides on another arbour, _p_, which may be the arbour of the great wheel of the striking part, attached by a ratchet and click to that wheel, or to the clock frame if there is no striking part. The weights are hung as may be seen, the small one being only large enough to keep the rope or chain on the pulleys. If the part _b_ of the rope or chain is pulled down, the ratchet-pulley runs under the click, and the great weight is pulled up by _c_, without taking its pressure off the going wheel at all.

Fig. 115. Triangular eccentric, giving an intermittent reciprocating rectilinear motion, often used for the valve motion of steam-engines.

Fig. 116. Ordinary crank-motion.

Fig. 117. In this, rotary motion is imparted to the wheel by the rotation of the screw, or rectilinear motion of the slide by the rotation of the wheel. Used in screw cutting and slide lathes.

Fig. 118. Uniform circular into uniform rectilinear motion; used in spooling frames for leading or guiding the thread on to the spools. The roller is divided into two parts, each having a fine screw-thread cut upon it, one a right and the other a left-handed screw. The spindle, parallel with the roller, has arms which carry two half nuts, fitting to the screw, one over the other under the roller. When one half nut is in, the other is out of gear. By pressing the lever to the right or left the rod is made to traverse in either direction.

Fig. 119. A system of crossed levers, termed "lazy tongs." A short, alternating rectilinear motion of rod at the right will give a similar, but much greater motion to the rod at the left. It is frequently used in children's toys. It has been applied to machines for raising sunken vessels; also applied to ship pumps three quarters of a century ago.

Fig. 120. Centrifugal governor for steam engines. The central spindle and attached arms and balls are driven from the engine by the bevel gears at the top, and the balls fly out from the centre by centrifugal force. If the speed of the engine increases, the balls fly out from the centre, raise the slide at the bottom, and thereby reduce the opening of the regulating valve, which is connected with the slide. A diminution of speed produces an opposite effect.

Fig. 121. Water-wheel governor acting on the same principle as Fig. 120, but by different means. The governor is driven by the top horizontal shaft and bevel gears, and the lower gears control the rise and fall of the shuttle or gate over or through which the water flows to the wheel. The action is as follows: The two bevel gears on the lower part of the centre spindle, which are furnished with studs, are fitted loosely to the spindle, and remain at rest so long as the governor has a proper velocity; but immediately the velocity increases, the balls flying farther out, draw up the pin, which is attached to a loose sleeve which slides up and down the spindle, and this pin, coming in contact with the stud on the upper bevel gear, causes that gear to rotate with the spindle, and to give motion to the lower horizontal shaft in such a direction as to make it raise the shuttle or gate, and so reduce the quantity of water passing to the wheel. On the contrary, if the speed of the governor decreases below that required, the pin falls and gives motion to the lower bevel gear, which drives the horizontal shaft in the opposite direction, and produces a contrary effect.

Fig. 122. Another arrangement for a water-wheel governor. In this the governor controls the shuttle or gate by means of the cranked lever, which acts on the strap or belt in the following manner: The belt runs on one of three pulleys, the middle one of which is loose on the governor spindle, and the upper and lower ones fast. When the governor is running at the proper speed the belt is on the loose pulley, as shown; but when the speed increases, the belt is thrown on the lower pulley, and thereby caused to act upon suitable gearing for raising the gate or shuttle and decreasing the supply of water. A reduction of the speed of the governor brings the belt on the upper pulley, which acts upon the gearing for producing an opposite effect on the shuttle or gate.

Fig. 123. Another form of steam-engine governor. Instead of the arms being connected with a slide working on a spindle, they cross each other, are elongated upward beyond the top, and connected with the valve-rod by two short links.

Figs. 124, 125. Diagonal catch and hand-gear used in large blowing and pumping engines. In Fig. 124 the lower steam valve and upper eduction valves are open, while the upper steam valve and lower eduction valve are shut; consequently the piston is ascending. In the ascent of the piston rod the lower handle will be struck by the projecting tappet, and being raised will become engaged by the catch, so as to shut the upper eduction and lower steam valves; at the same time the upper handle will be disengaged from the catch, the back weight will pull the handle up and open the upper steam and lower eduction valves, when the piston will consequently descend. Fig. 125 represents the position of the catches and handles when the piston is at the top of the cylinder. In going down, the tappet of the piston rod strikes the upper handle, and throws the catches and handles to the position shown in Fig. 124.

Fig. 126. A mode of driving a pair of feed rolls, the opposite surface of which require to move in the same direction. The two wheels are precisely similar, and both gear into the endless screw, which is arranged between them. The teeth of one wheel only are visible, those of the other being on the back or side which is concealed from view.

Fig. 127. Link-motion valve gear of a locomotive; two eccentrics are used for one valve, one for the forward and the other for the backward movement of the engine. The extremities of the eccentric rods are jointed to a curved slotted bar, or, as it is termed, a link, which can be raised or lowered by an arrangement of levers terminating in a handle, as shown. In the slot of the link is a slide and pin connected with an arrangement of levers terminating in the valve stem. The link, in moving with the action of the eccentrics, carries with it the slide, and thence motion is communicated to the valve. Suppose the link raised so that the slide is in the middle, then the link will oscillate on the pin of the slide, and consequently the valve will be at rest. If the link is moved so that the slide is at one of the extremities, the whole throw of the eccentric connected with that extremity will be given to it, the valve and steam ports will be opened to the full, and it will only be toward the end of the stroke that they will be totally shut; consequently the steam will have been admitted to the cylinder during almost the entire length of each stroke. But if the slide is between the middle and the extremity of the slot, as shown in the figure, it receives only a part of the throw of the eccentric and the steam ports will only be partially opened, and quickly closed again, so that the admission of steam ceases some time before the termination of the stroke, and the steam is worked expansively. The nearer the slide is to the middle of the slot the greater will be the expansion, and vice versa.

Fig. 128 represents a mode of obtaining motion from rolling contact. The teeth are for making the motion continuous, or it would cease at the point of contact shown in the figure. The fork catch is to guide the teeth into proper contact.

Fig. 129. What is called the Geneva-stop, used in Swiss watches to limit the number of revolutions in winding-up; the convex curved part of the wheel serving as the stop.

Fig. 130. A continuous rotary motion of the large wheel gives an intermittent rotary motion to the pinion-shaft. The part of the pinion shown next the wheel is cut of the same curve as the plain portion of the circumference of the wheel, and therefore serves as a lock while the wheel makes a part of a revolution, and until the pin upon the wheel strikes the guide-piece upon the pinion, when the pinion-shaft commences another revolution.

Fig. 131. The two crank-shafts are parallel in direction, but not in line with each other. The revolution of either will communicate motion to the other with a varying velocity, for the wrist of one crank working in the slot of the other is continually changing its distance from the shaft of the latter.

Figs. 132 and 133. These are parts of the same movement, which has been used for giving the roller motion in wool-combing machines. The roller to which the wheel F, (Fig. 132) is secured, is required to make 1/3 revolution backward, then 2/3 revolution forward, when it must stop until another length of combed fibre is ready for delivery. This is accomplished by the grooved heart-cam C, D, B, e, (Fig. 133) the stud working in the said groove; from C to D it moves the roller backward, and from D to e it moves it forward, the motion being transmitted through the catch G, to the notch wheel F, on the roller-shaft H. When the stud A arrives at the point e in the cam, a projection at the back of the wheel, which carries the cam, strikes the projecting piece on the catch G, and raises it out of the notch in the wheel F, so that while the stud is travelling in the cam from e to C, the catch is passing over the plain surface between the two notches in the wheel F, without imparting any motion; but when stud A arrives at the part C, the catch has dropped in another notch and is again ready to move wheel F and roller as required.

Fig. 134. An arrangement for obtaining variable circular motion. The sectors are arranged on different planes, and the relative velocity changes according to the respective diameters of the sectors.

Fig. 135. Intermittent circular motion of the ratchet-wheel from vibratory motion of the arm carrying a pawl.

Fig. 136. This represents an expanding pulley. On turning pinion _d_ to the right or left, a similar motion is imparted to wheel _c_, by means of curved slots cut therein, which thrust the studs fastened to arms of pulley outward or inward, thus augmenting or diminishing the size of the pulley.

Fig. 137 represents a chain and chain pulley. The links being in different planes, spaces are left between them for the teeth of the pulley to enter.

Fig. 138. Another kind of chain and pulley.

Fig. 139. Another variety.

Fig. 140 shows two different kinds of stops for a lantern-wheel.

Fig. 141. Intermittent circular motion is imparted to the toothed wheel by vibrating the arm B. When the arm B is lifted, the pawl C is raised from between the teeth of the wheel, and travelling backward over the circumference again drops between two teeth on lowering the arm, and draws with it the wheel.

Fig. 142. The oscillating of the tappet-arm produces an intermittent rotary motion of the ratchet-wheel. The small spring at the bottom of the tappet-arm keeps the tappet in the position shown in the drawing, as the arm rises, yet allows it to pass the teeth on the return motion.

Fig. 143. A nearly continuous circular motion is imparted to the ratchet-wheel on vibrating the lever _a_ to which the two pawls _b_ and _c_ are attached.

Fig. 144. An arrangement of stops for a spur-gear.

Fig. 145. A reciprocating circular motion of the top arm makes its attached pawl produce an intermittent circular motion of the crown-ratchet, or ray-wheel.

Fig. 146 represents varieties of stops for ratchet-wheel.

Fig. 147. Intermittent circular motion is imparted to the wheel A by the continuous circular motion of the smaller wheel with one tooth.

Fig. 148. A dynamometer, or instrument used for ascertaining the amount of useful effect given out by any motive power. It is used as follows: A is a smoothly turned pulley, secured on a shaft as near as possible to the motive power. Two blocks of wood are fitted to this pulley, or one block of wood and a series of straps fastened to a band or chain, as in the drawing, instead of a common block. The blocks, or block and straps, are so arranged that they may be made to bite or press upon the pulley by means of the screws and nuts on the top of the lever D. To estimate the amount of power transmitted through the shaft, it is only necessary to ascertain the amount of friction of the drum A when it is in motion, and the number of revolutions made. At the end of the lever D is hung a scale B, in which weights are placed. The two stops C C are to maintain the lever as nearly as possible in a horizontal position. Now, suppose the shaft to be in motion, the screws are to be tightened and weights added in B, until the lever takes the position shown in the drawing, at the required number of revolutions. Therefore the useful effect would be equal to the product of the weights, multiplied by the velocity at which the point or suspension of the weights would revolve if the lever were attached to the shaft.

Fig. 149 represents a pantagraph for copying, enlarging and reducing plans. One arm is attached to and turns on the fixed point C. B is an ivory tracing point, and A the pencil. Arranged as shown, if we trace the lines of a plan with the point B, the pencil will produce it double the size. By shifting the slide attached to the fixed point C and the slide carrying the pencil along their respective arms, the proportions to which the plan is traced will be varied.

Fig. 150. Anti-friction bearing. Instead of a shaft revolving in an ordinary bearing, it is sometimes supported on the circumference of wheels. The friction is thus reduced to the least amount.

Fig. 151. Releasing hook used in pile-driving machines. When the weight W is sufficiently raised, the upper ends of the hooks A, by which it is suspended, are pressed inward by the side of the slot B, in the top of the frame; the weight is thus suddenly released, and falls with accumulating force on to the pile-head.

Fig. 152. A and B are two rollers which require to be equally moved to and fro in the slot C. This is accomplished by moving the piece D, with oblique slotted arms, up and down.

Fig. 153. Centrifugal check-hooks, for preventing accidents in case of the breakage of machinery which raises and lowers workmen, or ores, in mines. A is a framework fixed to the side of the shaft of the mine, and having fixed studs D, attached. The drum on which the rope is wound is provided with a flange B, to which the check-hooks are attached. If the drum acquires a dangerously rapid motion, the hooks fly out by centrifugal force, and one or other, or all of them, catch hold of the studs D, arrest the drum, and stop the descent of whatever is attached to the rope. The drum ought besides this, to have a spring applied to it, otherwise the jerk arising from the sudden stoppage of the rope might produce a worse effect than its rapid motion.

Fig. 154. A sprocket-wheel to drive or to be driven by a chain.

Fig. 155. A combination movement, in which the weight W moves with a reciprocating movement, the down-stroke being shorter than the up-stroke. B is a revolving disc, carrying a drum which winds around itself the cord D. An arm C is jointed to the disc and to the upper arm A, so that when the disc revolves, the arm A moves up and down, vibrating on the point G. This arm carries with it the pulley E. Suppose we detach the cord from the drum, tie it to the fixed point, and then move the arm A up and down. The weight W will move the same distance, and in addition the movement given it by the cord, that is to say, the movement will be doubled. Now, let us attach the cord to the drum, and revolve the disc B, and the weight will move vertically with the reciprocating motion, in which the down-stroke will be shorter than the up-stroke, because the drum is continually taking up the cord.

Figs. 156, 157. The first of these figures is an end view, and the second is a side view of an arrangement or mechanism for obtaining a series of changes in velocity and direction. D is a screw on which is placed eccentrically the cone B, and C is a friction roller, which is pressed against the cone by a spring or weight. Continuous rotary motion, at a uniform velocity of the screw D carrying the eccentric cone, gives a series of changes of velocity and direction to the roller C. It will be understood that during every revolution of the cone the roller would press against a different part of the cone, and that it would describe thereon a spiral motion, the movement in one direction being shorter than that in the other.

Fig. 158. An engine governor. The rise and fall of the balls K are guided by the parabolic curved arms B, on which the anti-friction wheels L run. The rods F, connecting the wheel L with the sleeve, move it up and down the spindle C D.

Fig. 159. Toe and lifter for working poppet-valves in steam engines. The curved toe on the rock-shaft operates on the lifter attached to the lifting rod to raise the valve.

Fig. 160. Mercurial compensation pendulum. A glass jar of mercury is used for the bob or weight. As the pendulum-rod is expanded lengthwise by increased temperature, the expansion of mercury in the jar carries it to a greater height therein, and so raises its centre of gravity relatively to the rod sufficiently to compensate for downward expansion of the rod. As rod is contracted by a reduction of temperature, contraction of mercury lowers it relatively to rod. In this way the centre of oscillation is always kept in the same place, and the effective length of pendulum always the same.

Fig. 161. Compound bar compensation pendulum. C is a compound bar of brass and iron, or steel brazed together with brass downward. As brass expands more than iron, the bar will bend upward as it gets warmer, and will carry the weights W, W, up with it, raising the centre of the aggregate weight M, to raise the centre of oscillation as much as elongation of the pendulum-rod would let it down.

Fig. 162. Watch regulator. The balance-spring is attached at its outer end to a fixed stud R, and at its inner end to staff of balance. A neutral point is formed in the spring at P, by inserting it between two curb-pins in the lever, which is fitted to turn on a fixed ring concentric with staff of balance, and the spring only vibrates between this neutral point and staff of balance. By moving lever to the right, the curb-pins are made faster, and by moving it to the left, an opposite effect is produced.

Fig. 163. Compensation balance. _t_, _a_, _t´_ is the main bar of balance, with timing screws for regulation at the ends. _t_ and _t´_ are two compound bars, of which the outside is brass and the inside steel, carrying weights _b_, _b´_. As heat increases, these bars are bent inward, diminishing the inertia of the balance. As the heat diminishes, an opposite effect is produced. This balance compensates both for its own expansion and contraction, and that of the balance-spring.

Fig. 164. Parallel ruler, consisting of a simple straight ruler B, with an attached axle C, and a pair of wheels _A A_. The wheels, which protrude but slightly through the under side of the ruler, have their edges nicked to take hold of the paper and keep the ruler always parallel with any lines drawn upon it.

Fig. 165. Compound parallel ruler, composed of two simple rulers A, A, connected by two crossed arms pivoted together at the middle of their length, each pivoted at one end to one of the rulers, and connected with the other one by a slot and sliding pin, as shown at B. In this the ends as well as the edges are kept parallel. The principle of construction of the several rulers represented is taken advantage of in the formation of some parts of machinery.

Fig. 166. A simple means of guiding or obtaining a parallel motion of the piston rod of an engine. The slide _a_ moves in and is guided by the vertical slot in the frame, which has been planed to a true surface.

Fig. 167. Parallel motion for direct-action engines. In this, the end of the bar B C is connected with the piston-rod, and the end B slides in a fixed slot D. The radius bar F A is connected at F with a fixed pivot, and at A midway between the ends of B C.

Fig. 168. Oscillating engine. The cylinder has trunnions at the middle of its length, working in fixed bearings, and the piston rod is connected directly with the crank, and no guides are used.

Fig. 169. Inverted oscillating or pendulum engine. The cylinder has trunnions at its upper end, and swings like a pendulum. The crank shaft is below, and the piston rod connected directly with crank.

Fig. 170. Section of disc-engine. Disc-piston, seen edgewise, has a motion substantially like a coin when it first falls after being spun in the air. The cylinder heads are cones. The piston rod is made with a ball to which the disc is attached, said ball working in concentric seats in cylinder-heads, and the left-hand end is attached to the crank arm or fly-wheel on end of shaft at left. Steam is admitted alternately on either side of piston.

Fig. 171. The gyroscope, or rotascope, an instrument illustrating the tendency of rotating bodies to preserve their plane of rotation. The spindle of the metallic disc C is fitted to return easily in bearings in the ring A. If the disc is set in rapid rotary motion on its axis, and the pintle F at one side of the ring A is placed on the bearing in the top of the pillar G, the disc and ring seem indifferent to gravity, and instead of dropping begin to revolve about the vertical axis.

Fig. 172. Bohnenberger's machine, illustrating the same tendency of rotating bodies. This consists of 3 rings, _A_, _A´_, _A2_, placed one within the other, and connected by pivots at right angles to each other. The smallest ring, _A2_, contains the bearings for the axis of a heavy ball B. The ball being set in rapid rotation, its axis will continue in the same direction, no matter how the position of the rings may be altered; and the ring A2, which supports it, will resist a considerable pressure tending to displace it.

Fig. 173. What is called the gyroscope governor, for steam-engines, introduced by Alban Anderson in 1858. A is a heavy wheel, the axle _B B´_ of which is made in two pieces connected together by a universal joint. The wheel A is on one piece B, and a pinion I on the other piece _B´_. The piece B is connected at its middle by a hinge-joint with the revolving frame _H_, so that variations in the inclination of the wheel A will cause the outer end of the piece _B_ to rise and fall. The frame _H_ is driven by bevel gearing from the engine, and by that means the pinion 1 is carried round the stationary toothed circle _G_, and the wheel _A_ is thus made to receive a rapid rotary motion on its axis. When the frame H and wheel A are in motion, the tendency of the wheel A is to assume a vertical position, but this tendency is opposed by a spring L. The greater velocity of the governor, the stronger the tendency, above mentioned, and the more it overcomes the force of the spring, and the reverse. The piece B is connected with the valve rods by rods C, D, and the spring L is connected with the said rods by levers N and rod P.

Fig. 174. Pair of edge runners or chasers for crushing or grinding. The axles are connected with vertical shaft, and the wheel or chasers run in an annular pan or trough.

Fig. 175. Rotary motion of shaft from treadle by means of an endless band running from a roller on the treadle to an eccentric on the shaft.

Fig. 176. Tread-wheel horse-power turned by the weight of an animal attempting to walk up one side of its interior; has been used for driving the paddle-wheels of ferry-boats and many other purposes. The turn-spit dog used also to be employed in such a wheel in ancient times for turning meat while roasting on a spit.

Fig. 177. The treadmill, employed in jails in some countries for exercising criminals condemned to labour, and employed in grinding grain; turns by weight of person stepping on tread-boards on periphery. This is supposed to be a Chinese invention, and it is still used in China for raising water for irrigation.

Fig. 178. A. B. Wilson's four-motion feed, used in Wheeler and Wilson's, Sloat's, and other sewing machines. The bar A is forked, and has a second bar B, carrying the spur or feeder, pivoted in the said fork. The bar B is lifted by a radial projection on the cam C, at the same time the two bars are carried forward. A spring produces the return stroke, and the bar B drops of its own gravity.

Fig. 179. Mechanical means of describing parabolas, the base, altitude, focus, and directrix being given. Lay straight edge with near side coinciding with directrix, and square with stock against the same, so that the blade is parallel with the axis, and proceed with pencil in bight of thread, as in the preceding.

Fig. 180. Mechanical means of describing hyperbolas, their foci and vertices being given. Suppose the curves two opposite hyperbolas, the points in vertical dotted centre line their foci. One end of thread being looped on pin inserted at the other focus, and other end held to other end of rule, with just enough slack between to permit height to reach vertex when rule coincides with centre line. A pencil held in bight, and kept close to the rule, while latter is moved from centre line, describes one-half of parabola; the rule is then reversed for the other half.

Fig. 181. Cyclograph for describing circular arcs in drawings where the centre is inaccessible. This is composed of three straight rules. The cord and versed sine being laid down, draw straight, sloping line from ends of former to top of latter; and to these lines lay two of the rules crossing at the apex. Fasten these rules together, and another rule across them to serve as a brace, and insert a pin or point at each end of chord to guide the apparatus, which, on being moved against these points, will describe the arc by means of pencil in the angle of the crossing edges of the sloping rules.

Fig. 182. Proportional compasses used in copying drawings on a given larger or smaller scale. The pivot of compasses is secured in a slide which is adjustable in the longitudinal slots of legs, and capable of being secured by a set screw; the dimensions are taken between one pair of points and transferred with the other pair, and thus enlarged or diminished in proportion to the relative distances of the points from the pivot. A scale is provided on one or both legs to indicate the proportions.

Fig. 183. One of the many forms of rotary engine. A is a cylinder having the shaft B pass centrally through it. The piston C is simply an eccentric fast on the shaft, and working in contact with the cylinder at one point. The induction and eduction of steam take place as indicated by arrows, and the pressure of the steam on one side of the piston produces its rotation and that of the shaft. The sliding abutment D, between the induction and eduction ports, moves out of the way of the piston to let it pass.

Fig. 184. Another form of rotary engine, in which there are two stationary abutments D, D, within the cylinder; and the two pistons A, A, in order to enable them to pass the abutments, are made to slide radially in grooves in the hub C of the main shaft B. The steam acts on both pistons at once, to produce the rotation of the hub and shaft. The induction and eduction are indicated by arrows.

Fig. 185. Jonval turbine. The shutes are arranged on the outside of a drum, radial to a common centre, and stationary within the trunk or casing _b_. The wheel _c_ is made in nearly the same way; the buckets exceed in number those of the shutes, and are set at a slight tangent instead of radially, and the curve generally used is that of the cycloid or parabola.

Fig. 186. A method of obtaining a reciprocating motion from a continuous fall of water, by means of a valve in the bottom of the bucket which opens by striking the ground, and thereby emptying the bucket, which is caused to rise again by the action of a counterweight on the other side of the pulley over which it is suspended.

Fig. 187. Overshot water-wheel.

Fig. 188. Undershot water-wheel.

Fig. 189. Breast-wheel. This holds intermediate place between overshot and undershot wheels; has float-boards like the former, but the cavities between are converted into buckets by moving in a channel adapted to circumference and width, into which water enters nearly at the level of axle.

Fig. 190. Horizontal overshot water-wheel.

Fig. 191. A plan view of the Fourneyron turbine water-wheel. In the centre are a number of fixed curved chutes, or guides, A, which direct the water against the buckets of the outer wheel B, which revolves, and the water discharges at the circumference.

Fig. 192. Warren's central discharge turbine, plan view. The guides _A_ are outside, and the wheel _B_ revolves within them, discharging the water at the centre.

Fig. 193. Volate wheel, having radial vanes _A_, against which the water impinges and carries the wheel around. The scroll or volute casing _B_ confines the water in such a manner that it acts against the vanes all around the wheel. By the addition of the inclined buckets _c_, _c_, at the bottom, the water is made to act with additional force as it escapes through the openings of said buckets.

Fig. 194. Barker, or reaction mill. Rotary motion of central hollow shaft is obtained by the reaction of the water escaping at the ends of its arms, the rotation being in a direction the reverse of the escape.

Fig. 195 represents a trough divided transversely into equal parts, and supported on an axis by a frame beneath. The fall of water filling one side of the division, the trough is vibrated on its axis, and at the same time that it delivers the water the opposite side is brought under the stream and filled, which in like manner produces the vibration of the trough back again. This has been used as a water-meter.

Fig. 196. Persian wheel, used in Eastern countries for irrigation. It has a hollow shaft and curved floats, at the extremities of which are suspended buckets or tubs. The wheel is partly immersed in a stream acting on the convex surface of its floats; and as it is thus caused to revolve, a quantity of water will be elevated by each float at each revolution, and conducted to the hollow shaft at the same time that one of the buckets carries it full of water to a higher level, where it is emptied by coming in contact with a stationary pin placed in a convenient position for tilting it.

Fig. 197. Machine of ancient origin, still employed on the river Eisach, in the Tyrol, for raising water. A current keeping the wheel in motion, the pots on its periphery are successively immersed, filled, and emptied into a trough above the stream.

Fig. 198. Application of Archimedes screw for raising water, the supply stream being the motive power. The oblique shaft of the wheel has extending through it a spiral passage, the lower end of which is immersed in water, and the stream acting upon the wheel at its lower end produces its revolution by which the water is conveyed upward continuously through the spiral passage and discharged at the top.

Fig. 199. Common lift pump. In the upper-stroke of piston or bucket the lower valve opens and the valve in piston shuts; air is exhausted out of suction pipe, and water rushes up to fill the vacuum. In down stroke lower valve is shut and valve in piston opens, and the water simply passes through the piston. The water above piston is lifted up, and runs over out of spout at each up stroke. This pump cannot raise water over thirty feet high.

Fig. 200. Ordinary force pump, with two valves. The cylinder is above water, and is fitted with solid piston; one valve closes outlet pipe, and other closes suction pipe. When piston is rising suction-valve is open, and water rushes into cylinder, outlet valve being closed. On descent of piston suction valve closes, and water is forced up through outlet valve to any distance or elevation.

Fig. 201. Double-acting pump. Cylinder closed at each end, and piston-rod passes through stuffing-box on one end, and the cylinder has four openings covered by valves, two for admitting water and like number for discharge. A is suction pipe, and B discharge pipe. When piston moves down, water rushes in at suction valve 1, on upper end of cylinder, and that below piston is forced through valve 3 and discharge pipe B; on the piston ascending again, water is forced through discharge valve 4, on upper end of cylinder, and water enters lower suction valve 2.

Fig. 202. Common windmill, illustrating the production of circular motion by the direct action of the wind upon the oblique sails.

Fig. 203. Ordinary steering apparatus. Plan view. On the shaft of the hand wheel, there is a barrel on which is wound a rope, which passes round the guide-pulleys, and has its opposite ends attached to the tiller, or lever, on top of the rudder; by turning the wheel, one end of the rope is wound on and the other left off, and the tiller is moved in one or the other direction, according to the direction in which the wheel is turned.

Fig. 204. Capstan. The cable or rope wound on the barrel of the capstan is hauled in by turning the capstan on its axis by means of handspikes or bars inserted into holes in the head. The capstan is prevented from turning back by a pawl attached to its lower part and working in a circular ratchet on the base.

Fig. 205. Lewis bolt for lifting stone in building. It is composed of a central taper-pin or wedge, with two wedge-like packing pieces arranged one on each side of it. The three pieces are inserted together in a hole drilled into the stone, and when the central wedge is hoisted upon it, it wedges the packing pieces out so tightly against the sides of the hole as to enable the stone to be lifted.

Fig. 206. Tongs for lifting stones. The pull on the shackle which connects the two links causes the latter so to act on the upper arms of the tongs as to make their points press themselves against or into the stone. The greater the weight, the harder the tongs bite.

III

THE WEATHER AND INDOOR WORK

The measure of rainfall varies considerably within comparatively small areas, and this renders it no easy matter to get correct figures, so that the nearest records are those taken from a number of gauges within a limited district, and generalized. The more this is done, the less will be the inaccuracy in referring to the rainfall of any particular district or country.

If numerous rain-gauges were established throughout the country, and all their records sent to one central station, what valuable information might be collected for a particular district or country in the course of years. Means might be found for using the superabundant water, which falls in one part over another part, where the rainfall is less. Information such as this might be of special value in the West and South. It is collected now to a certain extent; but not done so generally as it ought to be.

As the fall of rain is always measured in inches gauges are made to indicate the equivalent of a cubic inch of rain on the surface of the earth. The simplest form of rain-gauge is a square or circular box or jar with a perfectly flat bottom and perpendicular sides (see Fig. 207). If the depth of water in such a gauge be measured after a fall of rain, one can ascertain in inches, or parts of an inch, the amount of rain that has fallen on the surface of the earth. Care must be taken to have the edge of the gauge thin and free from dents, the sides perpendicular and the bottom of the jar perfectly flat, for though in one measurement these irregularities may not make much difference, they would lead to a very decided error in a large number of measurements. Evaporation is also liable in such a gauge to give rise to errors, and extraneous matters are easily introduced. The better rain-gauges are constructed to avoid these contingencies, as far as possible and to depend only on the area of entry for the accuracy of the measurements. This area may be a square, but is usually circular for convenience. The circle must be accurate, and its area is then easily calculated, so that one can estimate the amount of rainfall, however large the receiving vessel may be. The edge of the circle, which may be made of copper, more durable than iron, must be sharp, with an overlapping rim to prevent raindrops from being whirled out of the receiver, and connected by a shoulder to a funnel, which directs the water into the receiver. This may be a glass bottle fitted with a cork to hold the funnel firmly, and prevent leakage between the outside of the funnel and the neck of the bottle (see Fig. 208). A more convenient receiver, and one less likely to be broken, is a round tin case of convenient size, with a top fitting accurately under the overlapping edge of the funnel-shaped cover. In this large receiver may be placed a small tin mug, with a lip just under the funnel, for conveniently measuring small quantities of rain, and preventing waste by evaporation. Any overflow from the mug will be caught in the large receiver (see Fig. 209). The circle of entry may, of course, be of any size; but one whose diameter is between 4 or 8 inches will be most convenient. Make the circle determine its area by careful measurement, using the following formula: D^2 × .7854 = area, each square inch will give cubic inches for area. Take this amount of water and pour it into a glass, marked at the top of the water, and then divide the intervening space between this mark and the bottom into 100 equal parts. This graduated glass will give the rainfall in inches and 100ths of an inch. As an inch glass is somewhat cumbersome, a half-inch glass is usually sent out with a rain-gauge. It may, however, be sometimes convenient to use an ordinary ounce measure, as graduated glass measures, when broken, are not always easily replaced; so that it may be necessary to find the corresponding relation between the cubic inches of receiving area and ounces and drachms. To do this, we will suppose the diameter of the circular top of gauge to be 4.7 inch; this squared = 22.09, multiplied by .7854 = 17.349486, divided by 1.733 (an ounce avoir. = 1.733 c. in.) = 10.011 oz. avoir.

Now if the rainfall is collected daily at a certain time in an ounce measure, the amount may easily be recorded in inches by reference to the accompanying table:

inch inch 10 oz. = 1.0000 1 oz. = .1000 9 " = .9000 7 dr. = .0875 8 " = .8000 6 " = .0750 7 " = .7000 5 " = .0625 6 " = .6000 4 " = .0500 5 " = .5000 3 " = .0375 4 " = .4000 2 " = .0250 3 " = .3000 1 " = .0125 2 " = .2000

A similar calculation can be made and table prepared for any larger circle of entry by the same method.

The amount of rainfall in any country is a matter of great importance to that country, and, like the rise of the Nile in Egypt, it indicates the coming state of the crops. If we have too small a rainfall, drought and withered crops follow, and if we get too great a fall of rain, drowned out crops, and disastrous floods occur, so you see how necessary it is that those people who are elected to look after the welfare of a nation, should keep posted on matters of rainfall in all its phases. In India, China and some other parts of the world the question of rainfall is one of life and death to the people, and most of the great famines of the past have been due to the small rainfall. Hundreds of thousands of people used to perish by famine and disease year after year. Much of this danger from shortage of rain has happily been avoided in India by the efforts of the British government, which has inaugurated and carried out great schemes of irrigation and artificial waterways to prevent the recurrence of famine from drought. Our own government also is expending large sums of money on irrigation plans now being executed in Arizona, Texas, Colorado and other states, which will render immense territories fit for cultivation, which would otherwise have remained barren and of no use. The matter of rainfall is of the highest importance to a nation and to the men and beasts inhabiting it.

"Will it rain to-day?" is a question frequently asked, as regards the weather, showing how important the subject is, and while I am talking on it, it may not be amiss to make a few remarks regarding the formation and distribution of rain, as formulated by learned meteorologists. We are told that the two great causes of rain are the sun and the ocean--the latter, of course, includes the great lakes and rivers--and since these two factors may be taken as constant, it follows that the rainfall over the earth as a whole will always be constant, while the local variations will be due to local conditions. The rain which falls on this continent is drawn up by the sun from the various sources, but the conditions which cause its precipitation may be said to be local. To your imagination may be left the tracing of the journey of the rain drops back to the ocean again. The starting points in considering the causes of rain are, therefore, heat and moisture. From the surface of land and water moisture is continually evaporating into the atmosphere, and the higher the temperature of the air the more watery particles it can hold. If any reduction in the temperature of this saturated air should take place, the vapour becomes visible as fog, mist, or cloud, and it is from this vapour that the rain drops are formed. Recent research says that these watery particles require minute dust atoms as nuclei before they can form, and it has been estimated, by experiment, that there are one thousand millions of them in a cubic foot of saturated air, though their total weight amounts to only 3 grains. Accepting these figures, the mathematically inclined may be told that it would require a cloud three miles thick to produce one inch of rainfall. But before these watery particles can fall to the earth as rain, they must first form into rain drops, and the question arises, how are rain drops formed?

These watery particles pass into the air by evaporation, and there are several ways by which the reduction in temperature necessary to render them visible can be brought about. It may take place through contact with a colder body of air, by expansion, or by a reduction of pressure owing to a rise in altitude. Clouds are said to be formed by this last method, for a volume of hot air rises higher and higher until it presently reaches a point when its contained vapour condenses, and becomes visible as a cloud. Meteorologists repeat one of these processes in the laboratory, by releasing from pressure damp air placed in a convenient glass globe, and are able to see something of the methods of cloud formation. It has been customary to speak of a cloud as being composed of watery particles floating motionless in the upper air; but although it may appear unchanged in form, it is all movement. So soon as ever a cloud is formed, its particles of moisture commence to fall slowly, the rate of fall being in proportion to the diameter of the particles, and this is due to the slight resistance the air makes to such very small atoms. In passing, it may be said that one observer estimates the diameter of these particles as from .00033 inch to .00025 inch. The component parts of a cloud are always in motion and recognizing this fact it becomes possible to take the first step in considering the formation of a raindrop.

An easy way out of the difficulty of explaining the formation of a raindrop, is to say that, since clouds are so often of two opposite electric potentials, there is always a continuous bombardment of watery particles taking place, and some of these must unite and fall as rain. The meteorologist is always tempted to call in electricity as an agency whenever he is anxious to discover a cause for some particular phenomenon. This often explains one mystery by another. The production of rain, snow, and hail has for many years been explained by vaguely ascribing them to the action of electricity, without any information being forthcoming as to the precise way in which this action takes place. Meteorologists are at present attempting to find a more satisfactory explanation. Another theory is that the particles of moisture in a cloud, like all other objects, radiate heat, and, growing cold, condense moisture upon their surfaces, thereby increasing in weight until they assume the proportions of a drop. This seemed a reasonable explanation of the formation of a rain drop until modern research decided that whenever moisture is condensed, latent heat is set free, so that all moisture deposited on a watery particle only serves to raise its temperature, and cause evaporation of the moisture thus acquired. The particles of water could not by this means grow to the full estate of a rain drop, and the theory is being gradually abandoned.

A rain drop is, according to modern meteorologists, explained in a very simple way. It has been seen how the hot, damp air is formed into a cloud, and also how the minute particles of water at once commence to fall slightly earthwards. Now these little particles as they pass into a warm layer of air would soon be evaporated, and would never reach the earth at all. Their downward journey, however, is often through a cloud many miles thick, and the most modern and simple theory is that in this journey they overtake some of their fellows, and the joined particles increase their rate of travel, overtake more and more particles until they presently become heavy enough to take the final plunge to earth. Were it possible to be just beneath a cloud, an observer would see rain drops coming from it of all sizes. The same process goes on in drops, which trickle down a window pane, or in the effervescing globules in a bottle of seltzer water. In the latter instance, the process is reversed, for the globules are seen overtaking one another in an upward direction. There are many points in favour of this theory of the formation of rain drops, and at least it gets rid of those elaborate complications, electricity and condensation. With respect to the formation of rain by the impinging of clouds upon the tops of cold mountains in the northwest, one authority argues that moisture is in these circumstances not condensed solely because of the contact with the cold hills; that rain there is due to a mechanical cause, the watery particles being squeezed together by the grinding effect of the clouds on the sides of the mountains in such a way that they coalesce, and fall as drops.

A rain drop's roundness is due to the action of capillarity. Just as a circle made by dropping a stone into water owes its shape to the fact that the force is able to act equally in all directions, so a rain drop is spherical, owing to similar untrammelled action on the part of capillarity. These are some of the explanations of the formation of a rain drop, but meteorologists still have the subject under consideration.

The periods of rainfall are divided broadly into times of drought and times of flood, and it is in these matters that meteorology is seen in its practical aspect. Some people ask, "Where does all the rain come from?" Others are surprised that rainfall totals up to such large quantities.

A fall of rain to a depth of one inch over a very limited area, represents millions of gallons, but in spite of this vast quantity of falling water, many times multiplied if the annual rainfall be taken into account, there still are water famines. The question has often been debated whether man can modify climate or effectively tamper with the processes which produce rain. Rain making has not, so far, been a success, though the firing off of heavy guns has been tried, along with the legitimate avocations of the meteorologist. The afforesting or deforesting of a district has, however, a marked effect upon rainfall. Three notable instances are Ascension Island, Malta, and the neighbourhood of the Suez Canal, where the planting of trees seems to have had the result of increasing the rainfall. The effect of trees is felt more in the storage of rain water, while leaves and roots serve to retain moisture that would otherwise quickly drain away. A hill may be converted into a sponge by the judicious planting of trees. The question of the storage of rain water becomes more pressing each year, and the longer the settlement is put off, the more difficult will decision become. Engineers called upon to prevent floods and to conserve rain water reply, "Save our forests, cover the land with trees."

The fact that such problems arise, serve to show how great is the amount of water formed by the continual falling of the tiny raindrops. As long as this beneficent downpouring is allowed to drain away unused or uncontrolled, so long will droughts annoy and water famines bring distress.

In recording weather conditions, symbols are sometimes used in order to shorten reports and, while not universal, most nations adopt these: The symbol for rain is o, a small circle filled in; for lightning [o]; for thunder T, while the two latter combined make T[o], the symbol for a thunder-storm. Nearly every weather component has a distinctive symbol, and since a great part of the meteorologist's work consists in going over records of observations to search for the number of times the different phenomena occur during each week or month, the task is much simplified when observers employ the symbols, as it is easier to pick out a symbol from a printed or written page than it is to recognize a word. These symbols, moreover, have been agreed upon as a sort of international notation, and make it easier for the meteorologists of different countries to understand the records of foreign meteorological services.

Everybody does not know the Russian word for snow, or the Dutch for hail, or the Bosnian for rain, but all who run, may read when "snow" is universally written, and hail represented by a wedge-shaped figure with lines drawn across. Time and space being limited, nearly all published records of weather merely set forth the number of days throughout the year on which the different phenomena occurred, and should snow, hail or thunder happen two or three times in one day, it would still be counted only as one day. The yearly totals, therefore, show the number of days on which these conditions have been observed. It is now an almost universal custom to count .01 inches or more during the twenty-four hours as a day of rain. Accordingly, where observers read their rain-gauge to three places of decimals, that on which less than .005 inch fell would not be counted as a rainy day. Smaller amounts would, however, be included in the total. Dew may sometimes fall to the amount of .01 in. or more; and that is counted as a rainy day, the rule being to consider the amount of precipitation, irrespective of the manner in which it has fallen. If you wish to make these observations comparable with published records you would do well to conform to these rules.

HAIL

Hail, the next weather component to be considered, presents many difficulties when the attempt is made to explain its origin and formation. Those who have anything to do with scientific matters are well acquainted with the hypothesis, which explains a given fact, and in considering the subject of hail, the meteorologist hears of many hypotheses which are put forward as complete explanations of this phenomenon. Caution is, therefore, to be exercised and every reported statement severely questioned. Remembering the aphorism: "The man or boy who never makes a mistake will never make anything," meteorologists have attacked the question of hail formation, and, although many mistakes have probably been made, the subject has lost a good deal of its mystery. For many years, it was customary to be content with a recognition of the fact that hail and lightning very often occur together, and the conclusion was drawn that the one was in some way responsible for the other. Sufficient corroboration of this hypothesis was to some meteorologists, found in the fact that thunder and lightning are said to be almost unknown in the Arctic regions, and this supposed companion, hail, almost unknown. Roughly speaking, the assumption was that lightning, as it flashed through a cloud laden with watery particles, caused hail to form. Such an explanation only tended to make the subject more mysterious, and the question, How is hail formed? practically remained unanswered. Many simpler explanations of hail have been propounded as the result of modern research, and, like rain and lightning, it has been demonstrated that hail owes its origin to the movement of the minute watery particles found everywhere in the atmosphere.

The clouds from which hail fall are ordinarily of great height above the earth, 40,000 feet or even higher. These are the well-known cirrus. The first condition necessary to the formation of hail is a powerful ascending current of hot, moist air, which may condense its moisture in the shape of the large woolly cloud, known as cumulus. Such a cloud may be 100 cubic miles in volume, and as long as it retains its shape nothing is likely to fall from it to the earth beneath. Before the formation of a thunder-shower, cirriform fibres in some instances break away from the upper portion of this cloud, the electrical tension is lowered, and rain falls. The coalescing of the particles of moisture has a great deal to do with the changes which take place in a cloud. All these changes take place in the higher clouds in a marked degree, and the varying strata through which the watery particles pass in ascending to and descending from this great height bring about the violent change essential to the formation of hail. The necessary conditions for hail are, therefore, a powerful, hot, ascending current of air and great variation in the strata of the atmosphere as regards moisture and temperature. Mountains assist in forcing currents of air upwards, and one mass of air impinging on another is also thrown upwards, so that condensation of moisture rapidly takes place. A hail cloud may be described as a tower of hot air, from the top of which, vapor is ejected into a frosty region. Hot plains are accordingly the most favourable spots for the formation of hail, and in mountainous districts, more hail falls at a distance from the mountains than among them. Snow is observed in all latitudes and at all heights, but hail is confined to middle latitudes, and is rare in high latitudes. The places most affected by hail are those in which, the temperature and humidity of the air are high, while above, at a great height, there is a cold area below the temperature of freezing point; but, as in the case of the rain drop, before anything can be definitely stated, it must be shown how the particles of moisture coalesce to form hail.

SNOW

Snow is frozen water which falls instead of rain when the temperature is below the freezing point. The ultimate constituents of snow are tiny, six-pointed crystals of ice. They assume in combination a thousand different figures (Fig. 210), all exceedingly beautiful. Professor Tyndall has shown, further, that the ultimate particles of ice are also these six-pointed stars. The white colour of snow is caused by the commingling of rays of all the prismatic colours from the minute snow crystals. Separately the crystals exhibit different colours.

Snow is usually from ten to twelve times as light as water, bulk for bulk; so that where the snow falls pretty evenly, the corresponding rainfall is readily determined by merely measuring the depth of snow and taking one tenth of the result. The more accurate plan, however, is to thrust the open end of a cylindrical vessel into the snow, invert the cylinder, and then melt the snow in it.

Snow plays an important part in the economy of nature. In the first place, the mere transformation of the water particles into ice is a process during which a large amount of heat is given out; so that we may regard the formation of snow renders the air currents warmer than they would otherwise be. Fallen snow serves to protect the ground, for, owing to its loose texture, it is a bad conductor of heat; so that, while checking the radiation of heat from the earth into space, it does not draw off the earth's heat by conduction. The ground is thus often 23 degrees to 30 degrees warmer than the surface of the snow above, and sometimes the difference of temperature has been more than 40 degrees.

Red snow and green snow have been met with, more commonly in Arctic regions, but also in other parts of the world. These colours are caused by the presence of minute organisms--a species of alga called _Protococcus nivalis_.

The snow line of mountains is on the slopes below which, all the snow which falls in the year, melts during the summer. Above the snow line, therefore, lies the region of perpetual snow. The altitude of the snow line depends on a variety of conditions. The latitude of a snow range is, of course, important in determining the position of the snow line, but many other circumstances have to be considered, as the shape and slope of the mountain, the aspect of either side of the range, the character of the surrounding country, the prevalent winds, and so on.

The following table shows the observed height of the snow line in feet above the sea level in different places:

Place Latitude Height Spitzbergen 78 N 0. Sulitelma, Sweden 67 5´ 3.835 Kamtchatka 59 30 5.240 Unalaschta 56 30 3.510 Altai 50 7.934 Alps 46 8.885 Caucasus 43 11.063 Pyrenees 42 45 8.950 Rocky Mountains 43 12.467 North Himalaya 29 19.560 South Himalaya 28 N 15.500 Abyssinian Mts. 13 14.065 Purace 2 2´ 15.381 Nevades of Quito 0 15.820 Arequipa, Bolivia 16 S 17.717 Paachata, Bolivia 18 12.079 Portillo, Chili 33 14.713 Cordilleras, Chili 42 30 6.010 Magellan Strait 53 30 3.707

DESIGNING, MAKING, AND INFLATING PAPER BALLOONS

Draw a rough figure of the balloon, as shown at A, (Fig. 211.)

Divide this into any number of parts (the more the better) by horizontal lines. Take a radius of balloon on each line, and describe circles, B.

Divide this into twelve parts by radius lines, then make pattern as follows: Draw a perpendicular, C, with horizontal lines at distance of horizontal lines on A, but measured on circumference as _c d_. Then set off on each line from perpendicular one half the distance between the radius lines, B, on the corresponding circle as _e f_; draw line through points thus found, and result will be shape of each section. Allow a little on one side when cutting out for pasting. This will be best made with strong tissue paper of any colour desired.

Another method, giving a shape somewhat different, is shown in Fig. 212. First draw an elevation of the balloon it is intended to make, either full size, on the floor, or to scale. The shape here illustrated differs slightly from that of balloons usually sold ready made, being wider at the mouth. This shape, however, is not so liable to catch fire when swayed about by the wind. Divide the elevation into any number of parts (the more the better) by horizontal lines as shown (No. 1). Take the radius of the balloon on each line, as A B, describe circles (No. 2), and divide these into twelve parts by radial lines. Then to make a pattern, draw a perpendicular (No. 3), with horizontal lines at the distance of the horizontal lines (No. 1,) but measured on the circumference as C D. Then set off on each line from the perpendicular half the distance between the radius lines (No. 2), on the corresponding circle as E F, and draw a line through the points thus found, and the result will be the shape of each section. Allow a little (say 1/4 inch), on one side when cutting out for pasting. Each section will be made up of one, two, or three pieces, according to the size of the balloon to be made. If the pieces are cut as shown (No. 4,) a great saving of paper results. To paste these pieces together, place them in a pile on the table or bench with the edges flush and a piece of waste paper under the pile. Now rub the top sheet with the thumb nail until each piece is moved back from the one immediately under it about one-fourth inch. Place a piece of waste paper about the same distance from the edge of the top sheet, and pass the paste brush over the whole of the exposed edges. No. 5 will explain what is meant. Now place two of the completed sections together so as to look like No. 3, with a small part projecting as shown by the dotted line G. Paste the edge of the under section--that is, the part hatched--and turn it over on to the dotted line H. When each two of the sections have been joined in this way, proceed in the same manner to join these together till the whole is completed. A circular piece of paper is cut out to join the sections at the top, and a loop of string should be pasted to the top to suspend the balloon while inflating. A ring of wire with two cross pieces is fitted to the bottom of the balloon, and the inflammable material,--tow soaked in methylated spirits--is fastened to the junction of the cross pieces.

MAGNETIZED WATCHES

The owner of a good American watch was a little troubled concerning it, because it had been running irregularly for some time past. It came out that he had visited the electric power house and had stayed for some time examining the works and machinery, so that parts of his watch had evidently become magnetized by the influence of the dynamos. The watch had been made some time ago, and had not the power to resist, or neutralize electric influences, that most watches have now.

To demagnetize the watch would bring it back to its original condition, but a second visit to the lighting plant would again spoil its time-keeping qualities. The watchmakers now have a way of making watches so that they are not affected by magnetism, but comparatively few of the time pieces in use are non-magnetic, and the average watch is subject to these seasons of fickleness.

The exceedingly fine and exact construction of the watch is not realized by the average possessor of the article. An examination of the works of a watch shows the mechanism as now constructed, although very small in size, to be accurately planned and executed. Changes of temperature are provided for, so that the movement is automatically adjusted. The mainspring and train of gears are usually concealed, while the balance and hair springs are in full view when the case is open. Upon the regularity of the movement of the balance depends the time keeping quality of the watch. On looking closely at the balance, you will observe that it is not a complete ring, but two halves supported at one end. These rings bear a number of large-headed screws, placed at irregular distances, which give it the exact weight and balance required. These half rings will also be found, on looking closely, to be composed of two metals so closely joined that a difference in colour alone gives evidence of the quality. This arrangement of iron and brass, on account of their different coefficients of expansion and contraction with changes of temperature, has been so carefully constructed that, with changes of temperature, the balance assumes such forms as to give it a uniform rate of motion.

The parts affected by magnetism are the balance and springs. The balance in an ordinary watch moves five times a second, 18,000 times an hour, and 432,000 times each day; but a slight change in the forces that move it is necessary to make a difference of several minutes each day. As the balance moves back and forth, the magnetism of the mainspring is pulling or pushing it. If this force were constant, and always in the same direction, the watch would run uniformly. Such, however, is not the case. When the mainspring is tightly wound, its magnetic poles are in a certain direction, and in unwinding they are constantly changing, so that the direction of this force is also constantly changed. The effect on the balance is to cause the watch to run too fast sometimes, and too slow at other times.

Non-magnetic watches are made with these parts of a non-magnetic metal, so that they are not influenced by electric machinery. For testing watches a small compass is used. When placed over the balance, the needle will vibrate with the motion of the balance in proportion to its magnetism.

A BOY'S WHEEL-BARROW

The bottom, sides, and ends were about three-quarters of an inch thick. Good white and red pine were used for the purpose. The stiles and rails of the bottom framework were mortised and tenoned together as shown at Fig. 213; these may be just stubbed together, or the tenons of the rails can go right through the stiles. The most satisfactory job is to groove the sides and ends together, and put all together with oil paint in the joints. If the joints are painted before the framework of the barrow is put together, it will last for years; otherwise, being a boy's wheel-barrow, it would likely often be forgotten and left out in the rain, and the joints getting wet would hasten decay. Two coats of good oil paint, Indian red, will give it a very nice appearance. This barrow, while not intended for heavy work, is capable of carrying quite a load. The wheel was cut out of a piece of plank about 1-1/2 inches thick, hooped up with an iron tire made from heavy hoop iron. The axle was made of wood with a 3/4-inch round iron rod running lengthwise through it and projecting about three inches through on each end. The arbours or boxing, in which ran the ends of the round rod, were formed on the ends of the handle stiles, as may be seen in the illustration. The cost of all the materials for this really useful article was less than $1.50, all told.

VACUUM CLEANERS

A single hand vacuum cleaner can be made from a powerful suction pump, as indicated in the sketch Fig. 214. This should be connected with a metallic box by means of a flexible armoured rubber hose, covered at the end with a piece of fine wire gauze to prevent large particles of dust, etc., being drawn into the pump. To another opening of the box should be fastened another flexible rubber tube, with a bell-shaped metal attachment at the end. The bell-shaped arrangement should be held closely to the carpet while the pump is in action. Within the box, the pipe to which the pump is attached should be bent upward, so that the rush of air shall not bring the dust with it; the object being to collect the dust in the box. A lid covers the box so that it can be emptied from time to time. The success of this arrangement depends on the strength of the pump; if it be a weak one, the inrush of air through the funnel will be so slight that the dust will not be raised.

Rotary pumps are not satisfactory for vacuum cleaners. The best type for this work is a plunger, having a large displacement, with a comparatively short stroke in proportion to the diameter. A suitable pump is shown in the accompanying illustrations. Fig. 214, shows the section of a single barrel, but should a greater supply be required, two barrels may be worked and connected as shown in Fig. 216. The pump is easily made, and of light construction. In Fig. 215, is a brass cylinder with a flange at the bottom; this may be made out of a length of 3-inch brass tube with a flange cut from 1/8-inch sheet brass. The barrel is 8 inches long. G is the plunger, which may be constructed as a piston; but in the drawing, it is adapted to the arrangement that is shown in Fig. 216. With a piston will be required a guide for the rod at the top of the cylinder. E is a hydraulic cup, its leather kept soft and pliable by oiling. B is the base, which is hollow, and may be built up in sheet metal. At the centre at J, the base is divided into two compartments, one side being the inlet to the pump from the dust box, and the other in communication with the outlet valve C. C and D are two valves with guards. The valves are discs of very soft and pliable leather, well saturated with grease, D being the inlet from the dust box, and C the outlet to the atmosphere. The drawing clearly shows the construction of the other parts. Fig. 216 shows two pumps fitted to one base and worked by a rocking lever; both pumps are in communication with the one inlet N. This arrangement of pumps is easy to work, portable, and well adapted to domestic purposes in cleaning carpets.

Fig. 217, which is reproduced from _The Scientific American_, exhibits an ingenious form of vacuum cleaner. It has recently been patented, and consists of a suction-fan operated by a water-motor that may be attached to the ordinary kitchen faucet. A tube is connected with the chamber of the suction-fan, and this terminates in a suitable nozzle, or foot plate, which may be moved over a carpet or rug to draw out the dust and dirt. One of the advantages of this system is that dirt drawn up by the suction fan can be carried away with the water down the kitchen drain.

A good power-driven cleaner may be made at home, says _Popular Mechanics_, by following these directions: First take a good pine board, 1 inch thick, 1 foot wide, and 3 feet long, and nail to each end a 1-foot length of 2-inch by 2-inch pine, as shown at A, Fig. 218. Next a 3/4-inch board, 1 foot wide and about 1 foot, 3 inches long, should be fastened near the centre, and at right angles to the first board, as shown at B. Procure a tin pan measuring about 10 inches in diameter and 3 inches deep. This pan shown at C, must be fitted with two valves, which are the most important and difficult part of the work. Cut, from a smooth piece of pine, 1 inch thick, two discs, 5 inches in diameter, with a 3-inch hole in the centre of each. Obtain a sheet of packing rubber, 1/8 of an inch thick, and cut from it two discs, each 5 inches in diameter, and two 3-1/2 inches in diameter. One of the discs of wood should be fastened to the back of the pan at the top, as shown at D, Fig. 219, with one of the 5-inch diameter rubber discs placed between the tin and the wood, and both secured to the tin by a row of small bolts around the outside edge of the wood. A hole, 3 inches in diameter, can now be cut through the tin and rubber, using the hole in the wood as a guide. Two discs with a diameter of 3-1/4 inches should be cut from cigar box wood and fastened centrally on the 3-1/2-inch rubber disc. One of the latter pieces should be fastened by its top edge to the top edge of the 5-inch disc of wood, as shown in E. This forms a flap valve, and great care should be taken to see that the rubber disc covers the opening all the way around when the valve is closed, so that it will be air-tight. A spring will be necessary to quicken the action of this valve. This is best made by fastening a narrow strip of wood across the valve opening on the inside of the pan, as shown at F, and attaching a rubber band to the centre of the valve and to this stick. This completes the outlet or exhaust valve. Another valve must now be made in the same manner, and fastened to the bottom of the pan on the inside, as shown. This is the inlet valve, and works in the opposite direction to the outlet valve just described.

Next procure a piece of leatherette about twelve inches in diameter, or large enough to cover the opening of the pan. This is to be used for the diaphragm. Cut a round hole about 8 inches in diameter in the upright piece B (Fig. 218), its centre about 7 inches from the top. From a piece of 1/2-inch pine, cut two discs 6 inches in diameter. Also secure a piece of hardwood H 1 inch by 1 foot 2 inches. The discs G should now be placed, one on each side of the leather diaphragm, exactly in the centre, and fastened to one end of the 1-foot 2-inch piece by means of a long screw. This piece H should exactly be in the centre of the diaphragm.

The pan can now be put in place. Set the diaphragm over the hole in the board B, the stick projecting through the hole. The pan is now placed over the diaphragm, and held by means of small bolts around the edge. The diaphragm between the wood and the tin acts as a gasket, and makes an air-tight joint.

Secure an air-tight tin about 8 inches in diameter and 12 inches high, and fasten it to the base board, as shown at J, Fig. 218. The cover of a coffee tin should now be soldered over the inlet valve, as shown at K, Fig. 219. Solder a hose connection in the centre of this cover, also one in the side of the tin, as shown at L, Fig. 218. Couple a short piece of hose M to these connections. The strainer S should be made of very strong and closely woven unbleached drill. Make it in the form of bag with a 1-inch hem at the top, and place it in the tin, as shown by the dotted line, the hem fitting closely over the inside edge of the tin. The cover of the tin is made from a flat pine board about one inch thick, and is held in place by two 1/4-inch rods fastened in the base board. These rods have thumb nuts on the top, which allow the cover to be readily removed or tightened down. It is best to place a rubber or leather gasket between the cover and the edge of the tin so as to make an air-tight joint.

An air-tight piece of garden hose can be used for the suction hose N, one end being fastened in the centre of the cover and the other to the brush or nozzle R, Fig. 218. It is best to buy this nozzle, as it would be rather expensive and unsatisfactory if home-made.

This machine may be driven by an electric motor of about 1-1/4 horse-power, which should be placed in the position shown in Fig. 218. The end of the connecting rod H is fastened to a crank on the motor shaft, and allowed to have about a one and one half inch stroke. The motor is wired up with a switch, P, and it would be best to connect to a rheostat, to allow the regulation of speed best suited to the machine. This can readily be determined after the machine is started. If an electric motor is not available, a small water motor will do equally well; or it may even be run by hand, by means of a long lever, fulcrumed at P.

The machine is now ready for using. First, however, test it all over for leakage, as its success depends on its being perfectly air-tight. As the motor revolves, the rod H is drawn forward, bringing with it the diaphragm. This creates a partial vacuum in the pan C, which opens the inlet valve, sucking the air through the suction hose and strainer, the air carrying with it the dust and dirt. The refuse is left in the strainer bag while the air goes on through the connecting hose and pan and outlet valve into the atmosphere. After the article being cleaned has been gone over thoroughly, care being taken to hold the nozzle against the material, the cover may be removed and the bag emptied.

IV

MOTORS AND TYPE-WRITERS

MOTORS, GASOLENE AND STEAM--AUTOMOBILE FRAMES--THE MODERN TYPE-WRITER--DIRECTIONS FOR SECURING COPYRIGHTS.

There are two classes of heat engines in use; in one class the combustion takes place on the inside of the cylinder or generator, just as fire is applied to a tea-kettle, and the heat is transmitted by conduction through the metal walls to the part of machine doing the work. Motors and machines of this kind, are generally called "external combustion" engines, of which the steam engine is a prominent example.

Engines where the combustion takes place inside the machine itself, and acts directly on it, are engines of the second class, termed "internal combustion engines." The gasolene engine is of this type, and so are all gas and oil engines.

The principle of the motor-cycle engine, in its action, is similar to the regular automobile engine and the gas engine. All these are internal combustion or explosion engines; that is, their motive power is derived from the force exerted by the explosion of a gas while under compression, the compressed gas generally ignited by means of an electric spark. In the case of gasolene motors, the gas is obtained from the liquid gasolene, either by allowing air to be drawn through it or by spraying the spirit through a small hole, the latter being the method most generally used. A great quantity of air has to be mixed with the vapour before it will ignite. The amount that is required varies considerably, atmospheric conditions and the height above sea level causing variations in the demand. The action of the common gasolene engine is known as the "four-stroke-cycle," that is, there are four strokes of the piston for every impulse, one being a "power" stroke and the other three "duty" strokes, as it were. Each performs a certain operation that is necessary for the correct working of the engine. Some engines are worked on the "two-stroke-cycle" principle; in this case, there are only two strokes for each impulse. This type of engine has many disadvantages, and there are very few two-stroke engines in use for driving motor cycles.

The principle of the "four-stroke-cycle" is shown in Figs. 220 to 223. In Fig. 220 the piston A is just beginning the downward stroke, and the valve B is opened by the pressure of the atmosphere, or by mechanical means. The piston in descending causes a partial vacuum in the cylinder head or top C, which allows the atmospheric pressure on the surface of the gasolene in the carburetor to force some of the liquid through the spray hole, thence through the inlet-valve opening D, into the compression space of the engine cylinder. The suction of the piston does not bring in the explosive mixture of gas and air; it is the pressure of the atmosphere that causes the mixture of gas and air to rush into the cylinder. Just before the piston is at the extreme end of the downward or outward stroke, the inlet valve B is closed by the spring shown, and the piston begins the first upward or "compression" stroke with both the inlet valve B and the exhaust valve E closed. The charge is being compressed when the piston is on its upward stroke, as shown in Fig. 221. Speaking generally, soon after the piston is over what is known as the "dead centre," and is about the position shown in Fig. 222, an electric spark is made to jump across two points of the sparking plug F; this ignites the mixture of gas and air (which is at a pressure of about 80 lb. per sq. in.), and the explosion causes the piston to descend on the power stroke. Just before the piston reaches the bottom of the power stroke, the exhaust valve E, Fig. 223, opens, and remains open during the upward stroke. The momentum of the flywheels, etc., carries the piston upward, and thus forces out the burnt gases through the exhaust opening G, and from there to the silencer. Immediately the piston begins its next downward stroke, the inlet valve opens, fresh air is drawn in, and the cycle of operations is repeated as before. The illustrations show a magneto gear driven by the engine.

These engines when properly arranged are made to do service as marine motors, and are then installed either horizontally or vertically. A vertical engine has been shown on previous pages, but perhaps a little further explanation may not be amiss. Engines for boats are made with one cylinder or with more, and there are many considerations which make an engine of two or more cylinders particularly desirable. It is a self-evident fact that when the limit of size of a single-cylinder is reached, it is necessary to add other cylinders if greater power is desired. Even for moderate or small powers, there are many advantages. Among these may be noted the fact that with the proper arrangement of cylinders the impulses may be made to occur at shorter intervals than with a single-cylinder engine. Thus with a two-cylinder engine, the cylinder may be so arranged that the impulses will occur twice for every revolution instead of once, as in a single-cylinder. This gives a more even turning effect to the shaft, and consequently steadier running, and it also requires a less heavy fly-wheel. The vibration is much less, as one set of working parts may be made to travel upward while the other is travelling downward, thus neutralizing the throw of each and lessening the vibration.

In case of the disablement of one cylinder, there is the chance of getting home on the remaining ones. The weight, power for power, of the multiple-cylinder engine is less than that of the single-cylinder engine, as the weight of the fly-wheel and other working parts is less.

While for marine work, single-cylinder engines have been built as large as eight or ten horse-power, they are so large as to be rather cumbersome and the practice now is to build engines of more than six horse-power with two or more cylinders. There are several firms who are making double-cylinder engines as small as four horse-power, which both as to weight and reliability are much superior to those of a single-cylinder.

The original method of constructing a multiple engine, and one which is still used by some builders, is simply to use two or more single-cylinder engines coupled together. This is a cumbersome method and takes up a great amount of space. The simplest method which can be recommended is that shown in Fig. 224. It consists of two single-cylinders mounted on a common base of special design, bringing the cylinders much nearer together than when a coupling is fitted to connect two separate engines--as the shaft can be made in one piece. This particular engine is of the two port type, two vaporizers V-V being used. The gasolene enters at G and branches to each vaporizer. The pump is shown at P with the discharge at W, piped with a branch to each cylinder. The cooling water outlet is at O. The exhausts are connected to a common pipe with the outlet at E. The igniting gear for each cylinder is independent and on opposite ends. By means of the lever L, which is connected to both igniting gears, the time of ignition is regulated and kept the same on both cylinders. This allows multiple-cylinder engines to be built with very few extra parts, as the cylinders, ignition gear, etc., are the same as in the single-cylinder engine.

A view of a representative single-cylinder engine is shown at Fig. 225. The cam shaft is located at _a_ and is driven by the gears which are shown just in the rear of the fly-wheel. At _c_ are the cam and the roller, which actuates the exhaust valve. The cam consists of a collar with a flat projection or toe upon its surface; the roller rests just above the surface of the collar, and is forced upward when struck by the projection. The roller is inserted to lessen the friction by rolling instead of rubbing. The valve stem extends upward into the valve chamber, and is encircled by the coiled spring _e_; the stem is guided by the guide at _g_. The exhaust is at E; I is the pipe leading from the vaporizer V to the inlet port in the valve chest. The inlet valve is directly below the spring S and is inverted, being held in place by the spring. The dome-shaped cap containing the inlet valve is removable for access to both valves. The complete cover is also removable. It will be observed that this engine has an open frame very similar to that of a steam engine, giving free access to the crank-pin and main bearings; the latter are shown fitted with oil boxes _b_ instead of the grease cups, as there is no pressure tending to force the oil out along the shaft as in the two-cycle type. This open base not only makes the bearings more accessible, but renders it easier to lubricate them and keep them cool. At H is the ignition gear. P is the cooling water pump, run by the eccentric _e_. The suction is piped to _d_ and the pump discharges through the pipe _k_ into the cylinder. The outlet for the cooling water is at O; N is the cylinder oil cup for oiling the bore of the cylinder. The compression cock R is for relieving the compression at starting. The coupling at X is for attaching the propeller shaft.

In this engine, the cylinder, base and bolting flange are one casting, the upper half of the main bearing being removable for the insertion of the shaft. The cover is bolted on separately.

AUTOMOBILE FRAMES

The chassis for the single-cylinder, eight horse-power motor machine shown herewith is built on the principle of most frames, of any make and is typical of the majority of light motor car chassis at present in use.

A diagrammatic plan of the eight horse-power, single-cylinder chassis is shown in the accompanying illustration (Fig. 226) in which, A indicates parts enclosed, taking the mixture of gasolene and air from the float-feed spray carburetor B, which has an automatic air regulator. The purpose of this last device is to dilute the mixture when the engine has a light load and is inclined to race; generally speaking, this regulator serves to proportion the ingredients of the explosive mixture to the requirements of the engine. Current O for the ignition of the explosive mixture (ignition occurs once for every two revolutions of the fly-wheel), is supplied by an accumulator and intensified by a high-tension coil. The products of combustion pass through the exhaust pipe C to the muffler D, from which they pass to the atmosphere through a series of fine holes. The starting handle E makes a simple connection with the end of the motor shaft F when required. G is the fly-wheel. The drive from the engine is through a universal joint H to the change-speed gear J, the latter consisting of two trains of toothed wheels, a big wheel on the primary shaft gearing with a small one on the secondary shaft to give a high speed, and vice versa. From the change-speed gear, the drive is through a shaft K, having a universal joint L at each end, to the bevel gearing above the differential gear of the live rear axle. Bevel gears and the differential gear are all contained in the casings M. Three brakes are fitted, one operated by pedal, working on a drum N secured to the propeller shaft, the others operated by the side lever and working on drums O O, secured to the rear wheels. The change-speed gear gives three speeds forward and a reverse; the frame is of pressed steel; the rod and wheels are of the artillery type and carry 700 mm. by 85 mm. pneumatic tires. The gasolene tank holds 4-1/2 gallons, sufficient for 200 miles, and the lubricating oil tank holds 1 gallon, sufficient for 350 miles. Any beginner in motoring matters, who studies the diagram, will obtain a fair idea of the mechanism of the customary type of light car chassis.

A chassis, suitable for a 7-1/2 horse-power quick-speed, two-cylinder motor, is shown in Fig. 227.

It is not necessary to enter fully into the details of construction after describing such a typical gear-driven car as that at Fig. 226.

The frame A is of tubular steel, there are four semi-elliptic springs, and the artillery wheels have 28-inch by 3-inch tires. The two-cylinder engine B is one casting, with a large waterway covered by an inspection plate C. The bore is 3.5 inches, stroke 4-inches, cylinder capacity 76.9 cubic inches, and the piston displacement is 92.300 cubic inches per minute. A governor automatically throttles the inlet when the motor attempts to race, but by means of a lever the governor can be cut out and the motor accelerated from its normal speed of 1,200 revolutions per minute. The balanced crank has but a single throw; the water circulation is assured by a motor-driven pump, and there is a belt-driven fan behind the radiator. The commutator is easily accessible, being mounted on a bevel shaft lying in a sloping position and passing through the side of the crank chamber. Ignition is high tension with wide contact, the wiring being enclosed in a neat wooden casing. The change-speed gear D gives three speeds and a reverse, and its main bearings are fitted with ring lubricators. A pressure sight feed lubricator on the dash-board has three outlets, one to the engine, another to the main clutch, and a third to the driving pinion on the end of the propeller shaft. The brakes are of the usual kind. In Fig. 227, E is the carburetor, F the inlet and G the exhaust pipes, H the exhaust muffler, J the brake pedal, K the clutch pedal, L the band-brake on the propeller shaft, and M the internal expanding brakes on the wheel hubs. A shield is arranged under the front of the car to protect the mechanism from mud and dust. The weight of the car unladen is about 1,414 pounds, the wheel base is 73-1/2 inches, the track 46 inches, and the over-all dimensions are 111 inches by 60 inches. During a 600-mile trial this engine consumed 36 gallons, 6 pints of gasolene, this being at the rate of 1 gallon for every 16.9 car miles; .077 gallon was consumed every ten miles.

THE MODERN TYPE-WRITER

Every home of importance contains a writing machine of some kind, and these often require some little adjustment or "fixing." It is within the capacity of any bright boy to make these adjustments, or to do the little fixings, if he tries it earnestly.

The first marketable type-writer was introduced in the year 1875. No sooner had the type-writer acquired a commercial value, than the fire of inventive talent was awakened in Europe and America, and type-writer after type-writer appeared on the market--a few came to stay, but the many disappeared, either during the chrysalis or experimental stage, or shortly after it had been passed. Inventors and investors have learned that hasty innovations and untried experiments spell "failure" in the type-writer field, and only patient and careful study, backed by experience, tireless effort, and abundant resource, have a chance of success.

By the year 1888, there were six different kinds of machines in the market, to-day there are at least twenty, but the favourites seem to be, "The Remington," "Smith Premier," "The Underwood" and "The Oliver."

Modern type-writers may be defined as being tabulating, book recording, card indexing, and document writing machines. They are speedier and produce finer and more varied work than their predecessors.

The manner in which the type-writer performs its work is of the simplest. The type-writer may be considered as composed of three general parts, as follows:

The keyboard, by which the operation of the machine is directed.

The type mechanism, by which the desired letters are, one after the other, in any desired sequence, imprinted on the paper.

The carriage, which holds the paper in proper position for writing, and which, by its regular movements, provides for the spacing of letters and lines.

The Remington may be considered the pioneer of writing machines. In appearance the Remington No. 5 (introduced in 1888) is square, and strikes a novice as being somewhat complicated. It is only the multiplicity of parts, however, which creates this impression. The machine is not complex, the same parts being repeated over and over again. The action is simplicity itself. The machine is quite open on every side, so that its entire construction can easily be seen. There is a japanned iron frame enclosing and holding the working parts, consisting of a base, four upright posts, and a top plate. In front is a series of keys arranged in four banks, like the keys of an organ, each key representing the two characters, termed "upper" and "lower" case letters. These are connected with long light wooden levers, which, being depressed, communicate motion by means of a rod fastened to the lever of a type bar. At the end of each type bar is fixed the hard metal type representing the two characters. The type bars are arranged in a circle, therefore the point of percussion of the type on the paper is at a common centre. The inking is done by a ribbon, which travels automatically across the machine, winding and rewinding on and from spools.

The paper is inserted between two rollers; one of rubber, called the "paper cylinder," and the other of wood, called the "feed roll." The rollers are held together by two elastic india-rubber bands. As one revolves so does the other. The portion which holds these rollers is designated the "carriage." By a clever, yet simple piece of mechanism, this carriage is caused to travel, simultaneously with the return of the type or spacing bar, from right to left, the width of a letter at each movement across the machine. The carriage works on a sliding frame, and this sliding mechanism is controlled by two keys, which do not impress letters on the paper. These change the character of the printing keys, causing them to print capitals or small letters, numerals or other marks at will. Depress the key marked "upper case" and all the keys will print capitals; remove the finger and they all print small letters again. Moreover, the machine can be arranged to print capitals continuously by the mere raising of a lever, and quite independently of the "upper case" shift key.

To obtain an impression, the required key is struck lightly, and the type bar causes the type to strike against the ribbon, thus leaving an imprint on the paper held round the cylinder; the carriage moves automatically the width of the letter, and the operation is repeated until a word is completed. Then the "spacing bar" at the front of the machine is depressed at any point, thereby securing the requisite space between the words.

When the end of a line is reached, warning is given by the ringing of a bell, and then, by pulling out the lever at the right-hand side of the carriage and gently pressing to the right, the paper carriage is advanced into position to receive the next line. The distance between the lines and the width of the writing can be regulated. The paper carriage being hinged at the back allows of its being raised from the front by the hand, so that the line that has just been written can be inspected.

The motive power is imparted by an adjustable coiled spring, a thin leather strap being fastened to it and the carriage, and the uniform space is governed by two clutches working on a rack. This rack is fixed on a rocking shaft, and derives a swinging motion from a universal bar fixed beneath the light wooden key levers.

A small lever attached to the left of the carriage holds its movements under the control of the operator. Two scales are fixed on the machine, and these in conjunction with the pointer, permit of head-lines being centred, corrections made, etc.

In some machines, a special key and its accompanying mechanism is provided for each character or sign used--such are termed "complete" keyboard machines. In others, each key is made to represent the letters or signs--such are designated "single-shift" machines. Others, again, have two shift-keys, and each key represents not only a lower case (small) and an upper case (capital) letter, but a figure or other sign as well--such are known as "double-shift" machines.

The two classes of modern type-writers may be arranged into three groups, namely:

"Blind" writers, in which the writing remains hidden until exposed by manipulative effort of the operator. "Semi-visible" writers, which show only the last lines, or only expose the centre of the paper, hiding the writing at both ends of the line. "Visible" writers, which expose a character directly in front of the operator the instant it is imprinted; the character subsequently does not pass out of sight, by feeding behind a scale or bar, or other obstruction. This classification and grouping is for convenience only, and is in no way intended to denote superiority.

With regard to the Remington, many changes of the details of construction, tending toward strength, durability, and a greater ease and convenience of operations, have been introduced into the machine, which have survived the severe test of time. This is especially the case with Remington No.7 (see Fig. 228). The most important of these valuable improvements are: An entirely new form of escapement, giving increased speed and an easy touch. The carriage is stronger and lighter, and steadier in all respects. The annoying rubber bands, which guide the paper around the platen have been discarded for a new form of paper guide, which may be adjusted to any desired point. The paper feed has been so arranged as to render it possible to write on wide or narrow paper, and this can be fed into the machine by a simple movement of the hand without lifting the carriage, and can be turned forward or backward at will. The ribbon movement is improved and works entirely automatically, reversing and giving a lateral movement. The marginal stops also are improved, and simple means provided for writing outside the margin whenever desired. There is a keyboard lock, locking the types at the end of the line, and thus preventing one letter being printed over another. A new variable line spacer is embodied, which makes it easier to write at any point on the paper, and prolongs the life of the platen for the reason that the type no longer strikes in unchanging grooves. An adjustable side guide for arranging the paper to any desired marginal indentation is a recent addition. A new two colour ribbon lever bearing a disc, which signals the color which the machine is adjusted to write is another recent addition.

The Smith-Premier type (Fig. 229) has six models in the market and all nearly alike in their mechanism, differing only in the carriage arrangements, or the number of the characters. The machine is particularly simple in construction, and claims, by means of a very long and strong adjustable bearing, to have secured a perfect and permanent alignment. The type bars work on hardened steel bearings, 1-5/8 inches apart, and the type bars are the shortest of any on a "complete" keyboard machine. But the original and exclusive feature of the machine is the rocking shaft, which replaces the usual wooden or metal key lever. This consists of a circular rod, passing from the front to the rear of the machine--one rod for each key. Projecting from each shaft is a small bar, which is attached at the front end to the lower portion of the key stem. A similar projection is attached to the rod communicating with the type bar, and the result is that on the depression of the key the rocking shaft is made to revolve slightly, and so raise the free end of the type bar to the printing point. The type bar hangers are solidly riveted to the type ring. It will be seen that matters are so arranged that the amount of force to imprint the character is precisely the same in every case--a uniform, light and elastic touch. A very noticeable feature is its quietness in operation, due to the rigidity of its parts, and the fact that the ball-bearing principle is adopted wherever it can be used to advantage. It is also equipped with a circular brush, built into the machine, into which a handle can be immediately inserted, when, with a turn or two, the whole of the type can be cleaned.

The most striking recent development is the adoption of a three-coloured ribbon device. A simple movement of the lever in front of the machine brings the required colour into place ready for use. A two-colour or single colour ribbon may be employed. If desired the ribbon can be instantly shifted from the printing point for duplicating purposes. The ribbon reverses automatically, and it is attached to the spools with clamps--one on each spool, dispensing entirely with pins and tapes.

The Oliver, Fig. 230, differs in mechanical principle from other machines. It has a wide U-shaped steel type bar, provided with a tool-steel axle as broad as the bar is long, and braced joints insuring the alignment without guides. The connection between the type bars and the key levers is direct and perpendicular. The type bars strike down on the platen in a line perpendicular to its plane, thus transmitting the maximum power with the minimum resistance, and further, maintaining the alignment with several sheets as with one. The type are of steel, and lie face upward--very convenient for cleaning. The keyboard is the "Universal," having twenty-eight keys with a "double" shift, giving eighty-four characters and the special model thirty-two keys, giving ninety-six characters.

The tension and depression of the keys are light and uniform. It may also be noted that the type blocks decrease in weight with the increase of length of type bar--necessary to secure a uniform stroke. The escapement mechanism is exceedingly simple and positive, and although very rapid is almost frictionless. The writing is semi-visible. The carriage is provided with three paper-feed rolls, thus ensuring a perfect feed of the paper down to the bottom edge of the sheet. It runs on anti-friction travellers on guide rails, ensuring an easy and steady motion. It is equipped with all the necessary devices. The line space mechanism operates automatically as the carriage is returned from the left to the right for a new line. The machine is compact and portable--weight about twenty pounds.

The parts of any of the machines now in the market, may readily be disconnected, but care must be taken by the novice in laying aside the parts so that they may be easily and correctly assembled. Repairs on the various parts may be made while out, and when made may be placed _in situ_. Any or all of the parts may be cleaned when the carriage is taken off. A little study of the machine when sitting before a person, will enable him to understand its mechanism, and when this is accomplished, cleaning and repairing can be done intelligently.

The tendency of the times is to employ the type-writer whenever possible. Special devices are from time to time invented to meet extended uses. The most important of recent applications is to office work for billing and book-keeping; this work alone has necessitated important modifications. In this direction, the tabulator calls for review. The lack of a practical method enabling tabular matter to be typed with a rapidity equal to that of the ordinary typing has long been felt to be a deficiency in type-writers. The invention of the tabulator has enormously increased the scope of the machine in this direction.

The tabulator is a device by means of which, figures or words can be written in columns, with out employment of the space bar or carriage release lever, or any adjustment whatever of the carriage by hand. By its use, the carriage may be set automatically at any point that may be required. At present this device is an accessory to most machines, but in the near future, it must form an integral part of all machines, and further, enable the carriage to be automatically placed in a proper position to write numbers in correct relation to each other in columns; that is, units under units, tens under tens, and so on. The built-in tabulators of to-day, with but two exceptions, are deficient in this respect. The tabulator in either form does not interfere with the use of the machine for other work, such as correspondence, etc.

The tabulator was followed by the introduction of a bi-chrome (two-coloured ribbon), and quite recently the Smith Premier Typewriter Company has advanced still further in this direction by introducing a tri-chrome (three-colour) ribbon. By a simple movement it is possible to vary the colour of the impression instantaneously, so that credits, marginal notes, footnotes, and underscoring may be indicated in red or other colour preferred. One-colour ribbons can be used if desired.

The machine embodying the parti-coloured ribbons and tabulator devices are generally known as "invoicing" machines, and by simple arrangements, every phase--not only of correspondence, but also of office and statistical work--can be accomplished, with an enormous saving of time. Items can be made on sheets, which may be taken from the machine with absolute certainty that when re-inserted, the subsequent entries will fall into their proper places.

_Card Indexing._--For greater convenience in card indexing, special platens are obtainable, or the ordinary platens can be temporarily fitted with a metal clip. Both can be fitted to or removed from the machine in a few seconds, and the cards can be adjusted in an instant. The increasing use of the card file system for a wide variety of purposes lends special importance to the value of the type-writer for this class of work.

_Interchangeable Carriages._--For years the thousand and one wide forms, statements, and blanks common in every business office, have been filled by the pen, the reason being that there was no machine practicable for both wide and ordinary work. The manufacturers of most of the modern type-writers now have models embodying interchangeable carriages, which enable any one possessing a machine with this improvement to have at the same time a set of carriages from the largest to the smallest, all of which can be used upon one machine. In one or two makes this is additional to interchangeable platens.

_Duplicators._--The value of a mechanical contrivance for the rapid and effective multiplication of copies of documents is fully recognized at the present time.

Duplicating machines have been on the market for several years. They will produce from one typescript original up to 3,000 copies, of any size, from a post card to a sheet of brief, every copy having the exact appearance of an original. While there are various makes and styles of duplicators, the main principle is the same throughout. The original is prepared by the now well-known stencil process; that is, writing the matter required with a type-writer on a sheet of waxed paper. The pressure of the type expels the wax out of the paper and leaves openings through which the ink can penetrate. In the Roneo rotary duplicator, a metal frame supports a cylinder of thin, perforated steel. On the outer surface of the cylinder is stretched a linen ink-pad, and over this is placed the stencil. The pad is inked by a rubber roller resting in an ink receptacle suspended between the two sides of the framework. By means of a simple lever this roller can be brought into contact with the cylinder, and ink is thus supplied as required. The cylinder is rotated by a handle. Paper fed into the machine is gripped by a rubber impression roller, which presses it against the stencil as the cylinder revolves, and the sheet perfectly printed, is then automatically discharged on the other side. The rotary can be fitted with three devices, namely a feeder, a simple contrivance, which automatically feeds the sheet into the machine, reducing hand labour to a minimum; an interlever, which automatically drops an interleaving sheet as each copy is printed--thus permitting of the use of highly glazed or very hard paper; a cyclometer for registering the number of copies. The rotary system is far superior to the hand duplicators in the matter of speed; such a machine will print ten copies while the hand device prints one. There is no lost motion, a copy being printed and discharged at every revolution.

_Press Copying._--At the present time, there are four methods of letter copying in vogue, namely: (1) The letter-book method, damping sheets and screw press. (2) Roller process, water bath and drying drum. (3) Carbon paper. (4) The chemical letter copier.

The roller copies employ a water bath, and give but little if any improvement in the regulation of the degree of moisture. The copies are wound on a drying drum to prevent off-setting, and subsequently have to be cut apart for filing purposes.

The carbon process enables the answers to be filed with the original letter.

The modern chemical letter copier offers distinct advantages over other methods. It consists of a simple machine designed to carry a roll of specially prepared paper. The letter to be copied is laid on the feed board, the handle is turned, the sheet is fed automatically into the machine.

It will be noticed that a water bath and brush or damping sheets, are completely dispensed with; there is no "off-sheeting" and no drying drum. The copy may be either filed with the letter to which it relates, or placed, day by day, in a cover having the appearance of an ordinary letter-book; or two copies can be made of each letter--one for filing and the other for the book.

(1). A type-writer should be durable. Every part should be simple and strong and adapted to serve its purpose with the smallest degree of wear. Every mechanical movement must be definite, and incapable of incomplete performance. All wearing parts should be adjustable and interchangeable.

(2). It should possess absolutely "visible" writing. The common-sense way to write easily and speedily is to see what you are writing while you are writing it.

The writing should be performed in such a part of the machine as to be most readily seen during progress.

(3). The keyboard--on type bar machines in particular--should be that known as the "Universal," or "Standard" arrangement.

The keys on any style of keyboard should have a light and uniform depression, so that the machine may be operated with the minimum of fatigue.

(4). The types should present an even and regular appearance, termed "alignment." A type bar made of suitable material in the right way is the keystone of typewriter construction. In all machinery, there is some part on which falls the greatest strain and wear; consequently on the durability of that part rests the life of the machine. The devices used to secure alignment are numerous and ingenious. One machine depends on a wide pivoted bearing and a rigid type bar; another has a bearing composed of a continuous steel rod, with a type bar flexible while in motion, and made rigid at the printing point by means of guides; a third employs a wide pivotal bearing, a flexible type bar and an indispensable guide plate at the printing point; a fourth employs a compound type bar and an indispensable guide at the printing centre, and so on. Some have wide and adjustable bearings, to enable the wear to be taken up. These devices, however, are not the only essentials. The type bar hangers in machines embodying the pivotal principle need to be rigid and solidly fixed, while the paper carriage should be perfectly rigid and present a level and even platen surface for the type to strike against.

(5). The type should be capable of being easily and quickly cleaned, and in such a way as not to injure the type or soil the hands. A device should be embodied for rendering it impossible to batter the face of the type when the type bars are accidentally struck one against the other, and for preventing the type perforating or puncturing the platen.

(6). The mechanism controlling the movement of the carriage should act rapidly and uniformly, and its tension should be adjustable. The carriage should have a sure and regular paper feed and be capable of accommodating any smaller width of paper; also the margin regulators and bell trip should be easily and readily altered.

(7). The platen roll should be instantly interchangeable, thereby allowing of a soft substance platen being used for a single copy work and a hard one for manifolding. If the hard platen is of reduced diameter, more perfect alignment is secured on machines employing a complete circle of rigid type bars and a central top carriage.

(8). The line-spacing mechanism should be variable, and effected by one movement at all times; that is, the same movement that accomplishes the line feed should be utilized to return the carriage for a new line.

(9). The ribbon movement should consist of a reliable feeding mechanism, and allow of the fabric being quickly withdrawn, replaced, or adjusted. It should bring the whole surface in contact with the type, and also automatically reverse the endwise travel.

(10). The machine should be as noiseless in operation as possible. Machines differ very much in this particular. The employment of the guides to force the alignment introduces metallic contact, and consequent friction and noise.

COPYRIGHTS

_Directions for Securing Copyrights, under the revised act of Congress, which took effect August 1, 1874._

(1). A printed copy of the title of the book, map, chart, dramatic or musical composition, engraving, cut, print, photograph, or a description of the painting, drawing, chromo, statue, statuary, or model or design for a work of the fine arts, for which copyright is desired, must be sent by mail or otherwise, prepaid, addressed: _Librarian of Congress_, Washington, D. C.

This must be done before publication of the book or other article. No entry can be made of a written title.

(2). A fee of fifty cents, for recording the title of each book or other article, must be enclosed with the title as above, and fifty cents in addition (or one dollar in all), for each certificate of copyright under seal of the Librarian of Congress, which will be transmitted by early mail.

(3). Within ten days after publication of each book or other article, two complete copies of the best edition issued must be sent, to perfect the copyright, with the address _Librarian of Congress_, Washington, D. C.

The postage must be prepaid, or else the publication enclosed in parcels covered by printed Penalty Labels, furnished by the Librarian, in which case they will come free by mail, according to rulings of the Postoffice Department. Without the deposit of copies above required the copyright is void, and a penalty of $25 is incurred. No copy is required to be deposited elsewhere.

(4). No copyright is valid unless notice is given by inserting in every copy published, on the title page or the page following, if it be a book; or if a map, chart, musical composition, print, cut, engraving, photograph, painting, drawing, chromo, statue, statuary, or model or design intended to be perfected as a work of the fine arts, by inscribing upon some portion thereof, or on the substance on which the same is mounted, the following words, viz: "Entered according to act of Congress, in the year----by----, in the office of the Librarian of Congress, at Washington," or, at the option of the person entering the copyright, the words: "Copyright, 19--, by----."

The law imposes a penalty of $100 upon any person, who has not obtained copyright, who shall insert the notice "Entered according to act of Congress," or "Copyright," etc., or words of the same import, in or upon any book or other article.

(5). Any author may reserve the right to translate or to dramatize his own work. In this case, notice should be given by printing the words "Right of translation reserved," or "All rights reserved," below the notice of copyright entry, and notifying the Librarian of Congress of such reservation, to be entered upon the record.

(6). Each copyright secures the exclusive right of publishing the book or article entered for the term of twenty-eight years. Within six months before the end of that time, the author or designer, or his widow or children, may secure a renewal for the further term of fourteen years, making forty-two years in all. Application for renewal must be accompanied by explicit statement of ownership, in the case of the author, or of relationship, in the case of heirs, and must state definitely the date and place of entry of the original copyright.

(7). The time within which any work entered for copyright may be issued from the press is not limited by any law or regulation, but depends upon the discretion of the proprietor. A copyright may be secured for a projected work as well as for a completed one.

(8). A copyright is assignable in law by any instrument of writing, but such assignment must be recorded in the office of the Librarian of Congress within sixty days from its date. The fee for this record and certificate is one dollar, and for a certified copy of any record of assignment one dollar.

(9). A copy of the record (or duplicate certificate) of any copyright entry will be furnished, under seal, at the rate of fifty cents each.

(10). In the case of books published in more than one volume, or of periodicals published in numbers, or of engravings, photographs, or other articles published with variations, a copyright is to be entered for each volume or part of a book, or number of periodical, or variety, as to style, title, or inscription, of any other article.

(11). To secure a copyright for a painting, statue, or model or design intended to be perfected as a work of fine arts, so as to prevent infringement by copying, engraving, or vending such design, a definite description must accompany the application for copyright, and a photograph of the same, at least as large as "cabinet size," should be mailed to the Librarian of Congress within ten days from the completion of the work or design.

(12). Copyrights cannot be granted upon Trade-marks, nor upon Labels intended to be used with any article of manufacture. If protection for such prints or labels is desired, application must be made to the Patent Office, where they are registered at a fee of $6 for labels and $25 for trade-marks.

(13). Every applicant for a copyright must state distinctly the name and residence of the claimant, and whether the right is claimed as author, designer, or proprietor. No affidavit or formal application is required.

OFFICE OF THE LIBRARIAN OF CONGRESS.

Transcriber's Notes.

Spelling appears to be evolving between US/UK e.g. both color and colour, vapor and vapours are seen.

Corrected obvious typos: guage -> gauge decending -> descending radical -> radial artifical -> artificial comtemplated -> contemplated barometor -> barometer p417. "namely [inserted 'a feeder'], a simple contrivance"

Chapter headings in Contents do not always match chapter headings in text. II. Building a Boathouse -> II. Building of a Boat House.

Inconsistent hyphenation left as printed: Both boat house and boat-house are used several times. Both typewriter and type-writer are used several times. Both Wheel-barrow and wheelbarrow are used several times. Both EVERYDAY and every-day are used several times.

Moved equations to single lines to make them clearer.

Some maths errors were found in the text, they have been corrected as follows:

p126. "find that it has taken five and one-third times as long, or 10 minutes to do this work." 10 should read 107.

p141. The equation P2[pi][nu] - Wp = 0 or -- = p2[pi][nu]/p should read: P2[pi][nu] - Wp = 0 or -- = P2[pi][nu]/p

p241. The equation (AB × CD)/2 × AB × 140 lb. = (2 - 3)/2 × 8/1 × 149 lb. = 2,800lb. should read (AB + CD)/2 × AC × 140 lb. = (2 + 3)/2 × 8/1 × 140 lb. = 2,800 lb.

p353. 1:733 -> 1.733

p141. and p142. For clarity, the numbering of the equations has been changed from a mixture of [N] and (N) to (N) only, and the mix of using [N.] and [N] have been changed so all numbering and references to the numbering have no "." The maths in this sequence of equations has gone wrong somewhere probably due to a mistyped w for W, r' for r'' or a missed divisor.

Corrected incorrect figure references: p297. D1 -> D´, E1 -> E´ p298. E1 -> E´ p299. G1 -> G´, H1 -> H´, G1 -> G, J1 -> J p401. Fig. 2 should be Fig. 227

Left as printed: Inconsistent use of italics between figures and text unless needed to make description in text unambiguous. Inconsistent hyphenation in measurements e.g. 7-1/2-in. and 3-1/2 in.