Chapter 5

The above are instances where science has come to the aid of engineering. Here is one in which the obligation is reversed. The rapid stopping of railroad trains, when necessary, by means of brakes, is a problem which has long occupied the attention of many engineers; and the mechanical solutions offered have been correspondingly numerous. Some of these depend on the action of steam, some of a vacuum, some of compressed air, some of pressure-water; others again ingeniously utilize the momentum of the wheels themselves. But for a long time no effort was made by any of these inventors thoroughly to master the theoretical conditions of the problem before them. At last, one of the most ingenious and successful among them, Mr. George Westinghouse, resolved to make experiments on the subject, and was fortunate enough to associate with himself Capt. Douglas Galton. Their experiments, carried on with rare energy and perseverance, and at great expense, not only brought into the clearest light the physical conditions of the question (conditions which were shown to be in strict accordance with theory), but also disclosed the interesting scientific fact that the friction between solid bodies at high velocities is not constant, as the experiments of Morin had been supposed to imply, but diminishes rapidly as the speed increases--a fact which other observations serve to confirm.

The old scientific principle known as the hydrostatic paradox, according to which a pressure applied at any point of an inclosed mass of liquid is transmitted unaltered to every other point, has been singularly fruitful in practical applications. Mr. Bramah was perhaps the first to recognize its value and importance. He applied it to the well known Bramah press, and in various other directions, some of which were less successful. One of these was a hydraulic lift, which Mr. Bramah proposed to construct by means of several cylinders sliding within each other after the manner of the tubes of a telescope. His specification of this invention sufficiently expresses his opinion of its value, for it concludes as follows: "This patent does not only differ in its nature and in its boundless extent of claims to novelty, but also in its claims to merit and superior utility compared with any other patent ever brought before or sanctioned by the legislative authority of any nation." The telescope lift has not come into practical use; but lifts worked on the hydraulic principle are becoming more and more common every day. The same principle has been applied by the genius of Sir William Armstrong and others to the working of cranes and other machines for the lifting of weights, etc.; and under the form of the accumulator, with its distributing pipes and hydraulic engines, it provides a store of power always ready for application at any required point in a large system, yet costing practically nothing when not actually at work. This system of high pressure mains worked from a central accumulator has been for some years in existence at Hull, as a means of supplying power commercially for all the purposes needed in a large town, and it is at this moment being carried out on a wider scale in the East End of London.

Taking advantage of this system, and combining with it another scientific principle of wide applicability, Mr. J.H. Greathead has brought out an instrument called the "injector hydrant," which seems likely to play an important part in the extinguishing of fires. This second principle is that of the lateral induction of fluids, and may be thus expressed in the words of the late William Froude: "Any surface which in passing through a fluid experiences resistance must in so doing impress on the particles which resist it a force in the line of motion equal to the resistance." If then these particles are themselves part of a fluid, it will result that they will follow the direction of the moving fluid and be partly carried along with it. As applied in the injector hydrant, a small quantity of water derived from the high pressure mains is made to pass from one pipe into another, coming in contact at the same time with a reservoir of water at ordinary pressure. The result is that the water from the reservoir is drawn into the second pipe through a trumpet-shaped nozzle, and may be made to issue as a stream to a considerable height. Thus the small quantity of pressure-water, which, if used by itself, would perhaps rise to a height of 500 feet, is made to carry with it a much larger quantity to a much smaller height, say that of an ordinary house.

The above are only a few of the many instances which might be given to prove the general truth of the fact with which we started, namely, the close and reciprocal connection between physical science and mechanical engineering, taking both in their widest sense. It may possibly be worth while to return again to the subject, as other illustrations arise. Two such have appeared even at the moment of writing, and though their practical success is not yet assured, it may be worth while to cite them. The first is an application of the old principle of the siphon to the purifying of sewage. Into a tank containing the sewage dips a siphon pipe some thirty feet high, of which the shorter leg is many times larger than the longer. When this is started, the water rises slowly and steadily in the shorter column, and before it reaches the top has left behind it all or almost all of the solid particles which it previously held in suspension. These fall slowly back through the column and collect at the bottom of the tank, to be cleared out when needful. The effluent water is not of course chemically pure, but sufficiently so to be turned into any ordinary stream. The second invention rests on a curious fact in chemistry, namely, that caustic soda or potash will absorb steam, forming a compound which has a much higher temperature than the steam absorbed. If, therefore, exhaust-steam be discharged into the bottom of a vessel containing caustic alkali, not only will it become condensed, but this condensation will raise the temperature of the mass so high that it may be employed in the generation of fresh steam. It is needless to observe how important will be the bearing of this invention upon the working of steam engines for many purposes, if only it can be established as a practical success. And if it is so established there can be no doubt that the experience thus acquired will reveal new and valuable facts with regard to the conditions of chemical combination and absorption, in the elements thus brought together.

WALTER R. BROWNE.

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HYDRAULIC PLATE PRESS.

One of the most remarkable and interesting mechanical arrangements at the Imperial Navy Yard at Kiel, Germany, is the iron clad plate bending machine, by means of which the heavy iron clad plates are bent for the use of arming iron clad vessels.

Through the mechanism of this remarkable machine it is possible to bend the strongest and heaviest iron clad plates--in cold condition--so that they can be fitted close on to the ship's hull, as it was done with the man-of-war ships Saxonia, Bavaria, Wurtemberg, and Baden, each of which having an iron strength of about 250 meters.

One may make himself a proximate idea of the enormous power of pressure of such a machine, if he can imagine what a strength is needed to bend an iron plate of 250 meters thickness, in cold condition; being also 1.5 meters in width, and 5.00 meters in length, and weighing about 14,555 kilogrammes, or 14,555 tons.

The bending of the plates is done as follows: As it is shown in the illustration, connected herewith, there are standing, well secured into the foundation, four perpendicular pillars, made of heavy iron, all of which are holding a heavy iron block, which by means of female nut screws is lifted and lowered in a perpendicular direction. Beneath the iron block, between the pillars, is lying a large hollow cylinder in which the press piston moves up and down in a perpendicular direction. These movements are caused by a small machine, or, better, press pump--not noticeable in the illustration--which presses water from a reservoir through a narrow pipe into the large hollow cylinder, preventing at the same time the escape or return of the water so forced in. The hollow cylinder up to the press piston is now filled with water, so remains no other way for the piston as to move on to the top. The iron clad plate ready to undergo the bending process is lying between press piston and iron block; under the latter preparations are already made for the purpose of giving the iron clad plate such a form as it will receive through the bending process. After this the press piston will, with the greatest force, steadily but slowly move upward, until the iron clad plate has received its intended bending.

Lately the hydraulic presses are often used as winding machines, that is, they are used as an arrangement to lift heavy loads up on elevated points.

The essential contrivance of a hydraulic press is as follows:

One thinks of a powerful piston, which, through, human, steam, or water power, is set in a moving up-and-down motion. Through the ascent of the piston, is by means of a drawing pipe, ending into a sieve, the water absorbed out of a reservoir, and by the lowering of the piston water is driven out of a cylinder by means of a narrow pipe (communication pipe) into a second cylinder, which raises a larger piston, the so-called press piston. (See illustration.)

One on top opening drawing valve, on the top end of the drawing pipe prevents the return of the water by the going down of the piston; and a barring valve, which is lifted by the lowering of the piston, obstructs the return of the water by the ascent of the piston, while the drawing valve is lifted by means of water absorbed by the small drawing pipe.--_Illustrirte Zeitung_.

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FAST PRINTING PRESS FOR ENGRAVINGS.

_Uber Land und Meer_, which is one of the finest illustrated newspapers published in Germany, gives the following: We recently gave our readers an insight into the establishment of _Uber Land und Meer_, and to-day we show them the machine which each week starts our paper on its journey around the world--a machine which embodies the latest and greatest progress in the art of printing. The following illustration represents one of the three fast presses which the house of Hallberger employs in the printing of its illustrated journals.

With the invention of the cylinder press by Frederick König was verified the saying that the art of printing had lent wings to words. Everywhere the primitive hand-press had to make way for the steam printing machine; but even this machine, since its advent in London in 1810, has itself undergone so many changes that little else remains of König's invention than the principle of the cylinder. The demands of recent times for still more rapid machines have resulted in the production of presses printing from a continuous roll or "web" of paper, from cylinders revolving in one given direction. The first of this class of presses (the "Bullock" press) was built in America. Then England followed, and there the first newspaper to make use of one was the _Times_. The Augsburg Machine Works were the first to supply Germany with them, and it was this establishment which first undertook to apply the principle of the web perfecting press (first intended for newspaper work only, where speed rather than fine work is the object sought) to book printing, in which far greater accuracy and excellence is required, and the result has been the construction of a rotary press for the highest grade of illustrated periodical publications, which meets all the requirements with the most complete success.

The building of rotary presses for printing illustrated papers was attempted as early as 1874 or 1875 in London, by the _Times_, but apparently without success, as no public mention has ever been made of any favorable result. The proprietor of the _London Illustrated News_ obtained better results. In 1877 an illustrated penny paper, an outgrowth of his great journal, was printed upon a rotary press which was, according to his statement, constructed by a machinist named Middleton. The first one, however, did not at all meet the higher demands of illustrated periodical printing, and, while another machine constructed on the same principle was shown in the Paris Exposition of 1878, its work was neither in quality nor quantity adequate to the needs of a largely circulated illustrated paper. A second machine, also on exhibition at the same time, designed and built by the celebrated French machinist, P. Alauzet, could not be said to have attained the object. Its construction was undertaken long after the opening of the Exposition, and too late to solve the weighty question. But the half-successful attempt gave promise that the time was at hand when a press could be built which could print our illustrated periodicals more rapidly, and a conference with the proprietors of the Augsburg Machine Works resulted in the production by them of the three presses from which _Uber Land und Meer_ and _Die Illustrirte Welt_ are to-day issued. As a whole and in detail, as well as in its productions, the press is the marvel of mechanic and layman.

As seen in the illustration, the web of paper leaves the roll at its right, rising to a point at the top where it passes between two hollow cylinders covered with felt and filled with steam, which serve to dampen the paper as may be necessary, the small hand-wheel seen above these cylinders regulating the supply of steam. After leaving these cylinders the paper descends sloping toward the right, and passes through two highly polished cylinders for the purpose of recalendering. After this it passes under the lowest of the three large cylinders of the press, winds itself in the shape of an S toward the outside and over the middle cylinder, and leaves the press in an almost horizontal line, after having been printed on both sides, and is then cut into sheets. The printing is done while the paper is passing around the two white cylinders. The cylinder carrying the first form is placed inside and toward the center of the press, only a part of its cog-wheel and its journal being shown in the engraving. The second form is placed upon the uppermost cylinder, and is the outside or cut form. Each one of the form cylinders requires a separate inking apparatus. That of the upper one is placed to the right at the top, and the bottom one is also at the right, but inside. Each one has a fountain the whole breadth of the press, in which the ink is kept, and connected with which, by appropriate mechanism, is a system of rollers for the thorough distribution of the ink and depositing it upon the forms.

The rapidity with which the impressions follow each other does not allow any time for the printing on the first side to dry, and as a consequence the freshly printed sheet coming in contact with the "packing" of the second cylinder would so soil it as to render clean printing absolutely impossible. To avoid this, a second roll of paper is introduced into the machine, and is drawn around the middle cylinder beneath the paper which has already been printed upon one side, and receives upon its surface all "offset," thus protecting and keeping perfectly clean both the printed paper and the impression cylinder. This "offset" web, as it leaves the press, is wound upon a second roller, which when full is exchanged for the new empty roller--a very simple operation.

The machines print from 3,500 to 4,000 sheets per hour _upon both sides_, a rate of production from twenty-eight to thirty-two times as great as was possible upon the old-fashioned hand-press, which was capable of printing not more than 250 copies upon _one side_ in the same time.

The device above described for preventing "offset" is, we believe, the invention of Mr. H.J. Hewitt, a well known New York printer, 27 Rose Street.

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FRENCH CANNON.

Five new cannons, the largest yet manufactured in France, have been successfully cast in the foundry of Ruelle near Angouleme. They are made of steel, and are breech loading. The weight of each is 97 tons, without the carriage. The projectile weighs 1,716 pounds, and the charge or powder is 616 pounds. To remove them a special wagon with sixteen wheels has had to be constructed, and the bridges upon the road from Ruelle to Angouleme not being solid enough to bear the weight of so heavy a load, a special roadway will be constructed for the transport of these weapons, which are destined for coast defences and ironclads.

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WOODLANDS, STOKE POGIS, BUCKS.

The illustration represents a house recently reconstructed. The dining-room wing was alone left in the demolition of the old premises, and this part has been decorated with tile facings, and otherwise altered to be in accordance with the new portion. The house is pleasantly situated about a mile from Stoke Church of historic fame, in about 15 acres of garden, shrubbery, and meadow land. The hall and staircase have been treated in wainscot oak, and the whole of the work has been satisfactorily carried out by Mr. G. Almond, builder, of Burnham, under the superintendence of Messrs. Thurlow & Cross, architects.--_The Architect_.

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CHINA GRASS.

The following article appeared in a recent number of the _London Times_:

The subject of the cultivation and commercial utilization of the China grass plant, or rhea, has for many years occupied attention, the question being one of national importance, particularly as affecting India. Rhea which is also known under the name of ramie, is a textile plant which was indigenous to China and India. It is perennial, easy of cultivation, and produces a remarkably strong fiber. The problem of its cultivation has long being solved, for within certain limits rhea can be grown in any climate. India and the British colonies offer unusual facilities, and present vast and appropriate fields for that enterprise, while it can be, and is, grown in most European countries. All this has long been demonstrated; not so, however, the commercial utilization of the fiber, which up to the present time would appear to be a problem only partially solved, although many earnest workers have been engaged in the attempted solution.

There have been difficulties in the way of decorticating the stems of this plant, and the Indian Government, in 1869, offered a reward of £5,000 for the best machine for separating the fiber from the stems and bark of rhea in its green or freshly cut state. The Indian Government was led to this step by the strong conviction, based upon ample evidence, that the only obstacle to the development of an extensive trade in this product was the want of suitable means for decorticating the plant. This was the third time within the present century that rhea had become the subject of official action on the part of the Government, the first effort for utilizing the plant dating from 1803, when Dr. Roxburg started the question, and the second from 1840, when attention was again directed to it by Colonel Jenkins.

The offer of £5,000, in 1869, led to only one machine being submitted for trial, although several competitors had entered their names. This machine was that of Mr. Greig, of Edinburgh, but after careful trial by General (then Lieutenant Colonel) Hyde it was found that it did not fulfill the conditions laid down by the Government, and therefore the full prize of £5,000 was not awarded. In consideration, however, of the inventor having made a _bona fide_ and meritorious attempt to solve the question, he was awarded a donation of £1,500. Other unsuccessful attempts were subsequently made, and eventually the offer of £5,000 was withdrawn by the Government.

But although the prize was withdrawn, invention did not cease, and the Government, in 1881, reoffered the prize of £5,500. Another competition took place, at which several machines were tried, but the trials, as before, proved barren of any practical results, and up to the present time no machine has been found capable of dealing successfully with this plant in the green state. The question of the preparation of the fiber, however, continued to be pursued in many directions. Nor is this to be wondered at when it is remembered that the strength of some rhea fiber from Assam experimented with in 1852 by Dr. Forbes Royle, as compared with St. Petersburg hemp, was in the ratio of 280 to 160, while the wild rhea from Assam was as high as 343. But, above and beyond this, rhea has the widest range of possible applications of any fiber, as shown by an exhaustive report on the preparation and use of rhea fiber by Dr. Forbes Watson, published in 1875, at which date Dr. Watson was the reporter on the products of India to the Secretary of State, at the India Office. Last year, however, witnessed the solution of the question of decortication in the green state in a satisfactory manner by M.A. Favier's process, as reported by us at the time.

This process consists in subjecting the plant to the action of steam for a period varying from 10 to 25 minutes, according to the length of time the plant had been cut. After steaming, the fiber and its adjuncts were easily stripped from the wood. The importance and value of this invention will be realized, when it is remembered that the plant is cultivated at long distances from the localities where the fiber is prepared for the market. The consequence is, that for every hundredweight of fiber about a ton of woody material has to be transported. Nor is this the only evil, for the gummy matter in which the fiber is embedded becomes dried up during transport, and the separation of the fiber is thus rendered difficult, and even impossible, inasmuch as some of the fiber is left adhering to the wood.

M. Favier's process greatly simplifies the commercial production of the fiber up to a certain point, for, at a very small cost, it gives the manufacturer the whole of the fiber in the plant treated. But it still stops short of what is required, in that it delivers the fiber in ribbons, with its cementitious matter and outer skin attached. To remove this, various methods have been tried, but, as far as we are aware, without general success--that is to say, the fiber cannot always be obtained of such a uniformly good quality as to constitute a commercially reliable article. Such was the position of the question when, about a year ago, the whole case was submitted to the distinguished French chemist, Professor Fremy, member of the Institute of France, who is well-known for his researches into the nature of fibrous plants, and the question of their preparation for the market. Professor Fremy thoroughly investigated the matter from a chemical point of view, and at length brought it to a successful and, apparently, a practical issue.