CHAPTER XII

RULES OF THUMB

MINING APPLIANCES AND METHODS

A TEMPORARY FORGE.

What prospector has not at times been troubled for the want of a forge? To steel or harden a pick, or sharpen a drill is comparatively easy, but there is often a difficulty in getting a forge. Big single action bellows are sometimes bought at great expense, and some ingenious fellows have made an imitation of the blacksmith’s bellows by means of sheepskins and rough boards.

With inadequate material and appliances to hand, the following will be found easier to construct and more lasting when constructed. Only a single piece of iron is required, and, at a pinch, one could even dispense with that by using a slab of talcose material, roughly shaping a hearth therein and making a hole for the blast. First, construct a framing about the height of an ordinary smith’s forge. This can be made with saplings and bark, or better still, if available, out of an empty packing case about three feet square. Fill the frame or case with slightly damped earth and ram it tight, leaving the usual hollow hearth. Then form a chamber below the perforated hearth opening to the rear. Now construct a centrifugal fan, such as is used for the ventilation of shallow shafts and workings. Set this up behind the hearth and revolve by means of a wooden multiplying wheel. A piece of ordinary washing line rope, or sash line rope, well resined if resin can be got--but pitch, tar, or wax will do by adding a little fine dust to prevent sticking--is used as a belt. With very rough materials a handy man can thus make a forge that will answer ordinary requirements.--N.B. Do not use clay for your hearth bed unless you can get a highly aluminous clay, and can give it full time to dry before the forge fire is lit. Ordinary surface soil, not too sandy, acts well, if damped and rammed thoroughly. Of course, if you can get an iron nozzle for your blower the whole operation is simplified.

SIMPLE WAY OF MAKING CHARCOAL.

Dig a pit 5 feet square by 3 feet deep and fill with fuel. After lighting, see that the pit is kept full. The hot embers will gradually sink to the bottom. The fuel should be kept burning fiercely until the pit seems almost full, when more fuel should be added, raising the heap about a foot above the level of the ground. The earth dug out of the pit should then be shovelled back over the burning mass. After leaving it to cool for 24 hours the pit will be found nearly full of charcoal. About one-quarter the weight of the dry fuel used should be recovered in charcoal.

ROUGH SMELTING ON THE MINE.

Rough gold smelting on the mine is effected with a flux of borax, carbonate of soda, or, as I have often done, with some powdered white glass. When the gold is smelted and the flux has settled down quietly in a liquid state, the bulk of the latter may be removed, to facilitate pouring into the mould, by dipping an iron rod alternately into the flux and then into a little water, and knocking off the ball of congealed flux which adheres after each dip. This flux should, however, be crushed with a pestle and mortar and panned off, as, in certain cases, it may contain tiny globules of gold.

MISFIRES IN BLASTING.

One of the most common sources of accident in mining operations is due either to carelessness or to the use of defective material in blasting. A shot misses, generally for one of two reasons; either the explosive, the cap, or the fuse (most often the latter), is inferior or defective; or the charging is incompetently performed. Sometimes the fuse is not placed properly in the detonator, or the detonator is not properly enclosed in the cartridge, or the fuse is injured by improper tamping. If several shots have been fired together, particularly at the change of a “shift,” the men who have to remove the broken material may in so doing explode the missed charge. Or, more inexcusable still, men will often be so foolish as to try to clear out the drill hole and remove the missed cartridge. When a charge is known to have missed all that is necessary to do in order to discharge it safely is to remove a few inches of “tamping” from the top of the drill hole, place in the bore a plug of dynamite with cap and fuse attached, put an inch or two of tamping over it and fire, when the missed charge will also be exploded. Of course, judgment must be used and the depth of the drill taken into consideration. As a rule, miners use far more tamping than is at all requisite. The action of the charge will generally be found quite as effective with a few inches of covering matter as with a foot or more, while the exploding of misfire cartridges is rendered simple, as no removal of tamping is required before placing the top “plug” in case of misfire.

TO PREVENT LOSS OF RICH SPECIMENS IN BLASTING.

When blasting the cap of a lode, particularly on rich shutes of gold, the rock is apt to fly, and rich specimens may be thrown far afield and so be lost. A simple way of avoiding this is to procure a quantity of boughs, which tie into loose bundles, placing the leafy parts alternately end for end. Before firing, pile these bundles over the blast and, if care is used, very few stones will fly. The same device may be used in wide shallow shafts.

A SIMPLE MODE OF RETORTING SMALL QUANTITIES OF AMALGAM.

Clean your amalgam and squeeze it as hard as possible through strong calico or chamois leather. Take a large sound potato, cut off about a quarter from one end and scoop out a hole in the centre about twice as big as the ball of amalgam. Procure a piece of flat iron--an old spade will do as well as anything--insert the amalgam, and, having placed the potato, cut side downwards, thereon, put the plate of iron on the forge, heat up first gently, then stronger, till separation has taken place, when the gold will be found in a bright clean button on the plate and the mercury in fine globules in the potato, from which it can be re-collected by breaking up the partly or wholly cooked tuber under water in an enamelled or ordinary crockery basin. It is as well to place a piece of paper between the iron and the amalgam to prevent adhesion.

TO RETORT SMALL QUANTITIES OF MERCURY FOR AMALGAMATING ASSAY TESTS.

Get two new tobacco pipes similar in shape (Fig. 34), with the biggest bowls and longest stems procurable. Break off the stem of one close to the bowl and fill the hole with well worked clay (some battery slimes make the best luting clay). Set the stemless pipe on end in a clay bed, and fill with amalgam, pass a bit of thin iron or copper wire beneath it, and bend the ends of the wire upwards. Now fit the whole pipe, bowl inverted, on to the under one, luting the edges of both well with clay. Twist the wire over the top with a pair of nippers till the two bowls are fitted closely together, and you have a retort that will stand any heat necessary to thoroughly distil mercury.

A SIMPLE MODE OF ASCERTAINING THE NOMINAL HORSE-POWER OF AN ENGINE.

Multiply the internal diameter of the cylinder by itself and strike off the last figure of the quotient. The diameter is

20” × 20” 20 ----- 40ø. The H.P. is 40.

The following rules will be found more professionally accurate from an engineering standpoint, though the term “horse-power” is not now generally employed.

_To find the Nominal Horse-power._--For _non-condensing_ engines: Multiply the square of the diameter of the cylinder in inches by 7 and divide the product by 80. For _condensing_ engines: Multiply the square of the diameter of the cylinder in inches by 7 and divide the product by 200.

_To find the Actual Horse-power_ of an engine, multiply the area of the cylinder in square inches by the average effective pressure in pounds per square inch, less 3 lb. per square inch as the frictional allowance, and also by the speed of the piston in feet per minute, dividing the product by 33,000, and the quotient will be the actual horse-power.

“SCALING” COPPER PLATES.

To “scale” copper plates they may be put over a charcoal or coke fire to slowly sublimate the quicksilver. Where possible, the fireplace of a spare boiler can be utilised, using a thin red fire. After the entire evaporation of the quicksilver the plates should be slowly cooled, rubbed with hydrochloric acid, and put in a damp place overnight, then rubbed with a solution of sal ammoniac and nitre in equal parts, and again heated slowly over a red fire. They must not be allowed to get red hot; the proper degree of heat is indicated by the gold scale rising in blisters, when the plates are to be taken from the fire and the gold scraped off. Any part of the plate on which the gold has not blistered should be again rubbed with the solution and fired. The gold scale should be collected in a glass or earthen dish and covered with nitric acid, till all the copper is dissolved, when the gold can be smelted in the usual way; but when it is molten, corrosive sublimate should be put in the crucible till a blue flame ceases to be given off.

_A Second Method._

The simplest plan I know is to have a hole dug nine inches deep by about the size of the plate to be scaled; place a brick at each corner, and on each side, halfway between. Get up a good fire, and let it burn down to strong embers, or use charcoal, then place the plate on three bars of iron extending between the three pairs of bricks, have a strong solution of borax ready in which soak strips of old “table blanket,” laying these over the plate and sprinkling them with the borax solution when the plate gets too hot. After a time the deposit of mercury and gold on the plate will assume a white, efflorescent appearance, and may then be readily parted from the copper.

_Another Method._

Heat the plate over an open fire, to drive off the mercury; after which, let it cool, and saturate with dilute sulphuric acid for three hours, or longer; then sprinkle over the surface a mixture of equal parts of common salt and sal ammoniac, and heat to redness. When cool, the gold scale comes off freely; the scale is then boiled in nitric or sulphuric acid, to remove the copper, previous to melting. Plates may be scaled about once in six months, and will under ordinary circumstances produce about one ounce of clean gold for each superficial foot of copper surface employed. I always paint the back of the plate with a mixture of boiled oil and turpentine, or beeswax dissolved in turpentine, to prevent the acid attacking the copper.

HOW TO SUPPLY MERCURY TO MORTAR BOXES.

I am indebted for the following to Mr. J. M. Drake, who, speaking of his experience on the Wentworth Mine, N.S.W., says:--

“Fully 90 per cent. of the gold is saved on the outside plates, only a small quantity remaining in the mortar. The plates have a slope of 2 in. to 1 ft. No wells are used, the amalgam traps saving any quicksilver which may leach off the plates. The quicksilver is added every hour in the mortar. The quantity is regulated by the mill manager in the following manner: Three pieces of wood, 8 in. wide by 12 in. long by 2 in. thick, have 32 holes 1 in. deep bored in each of them. These holes will just take a small 2 oz. phial. The mill manager puts the required quantity of quicksilver in each bottle and the batteryman empties one bottle in each mortar every hour; and puts it back in its hole upside down. Each block of wood lasts eight hours, the duration of one man’s shift.” This of course is for a 20-head mill with four mortars or “boxes.”

I commend this as an excellent mode of supplying the mercury to the boxes or mortars. The quantity to be added depends on circumstances. A careless battery attendant will often put in too much or too little when working without the automatic feeder. I have known an attendant on suddenly awaking to the fact half through his shift, that he had forgotten to put in any mercury, to then empty into the stamper box two or three pounds weight; with what effect may be easily surmised.

HOW WATER SHOULD ENTER STAMPER BOXES.

The following extract which relates to Californian Gold Mill practices is from Bulletin No. 6 of the California State Mining Bureau. I quite agree with the practice.

“The battery water should enter both sides of the mortar in an even quantity, and should be sufficient to keep a fairly thick pulp which will discharge freely through the grating or screen. About 120 cubic feet of water per ton of crushed ore may be considered an average, or 8 to 10 cubic feet per stamp per hour.

“Screens of different materials and with different orifices are used; the materials comprise wire cloth of brass or steel, tough Russian sheet iron, English tinned plate, and, quite recently, aluminium bronze. The ‘aluminium bronze’ plates are much longer lived than either of the other kinds, and have the further advantage that, when worn out, they can be sold for the value of the metal for remelting; these plates are bought and sold by the pound, and are said to contain 95 per cent. of copper and 5 per cent. of aluminium. Steel screens are not so much used, on account of their liability to rust.”

I have had no experience with the aluminium bronze screen. I presume, however, that it is used only for mills where mercury is not put in the mortars, otherwise it would surely become amalgamated. The same remark applies to brass wire cloth and tinned plate. Unless the metal of which they are composed will not readily amalgamate with mercury, I should be chary of using new screen devices. Mercury is a most insidious metal and is often found most unexpectedly in places in the battery where it should not be. Probably aluminium steel would be better than any substance mentioned. It would be hard, light, strong, and not readily corrodible. I am not aware if it has been tried.

Under the heading of “Power for Mills” the following is taken from the same source.

POWER FOR MILLS.

“As the Pelton wheel seems to find the most frequent application in California, it may be convenient for millmen to have the following rule, applicable to these wheels:

“When the head of water is known in feet, multiply it by 0·0024147, and the product is the horse-power obtainable from one miner’s inch of water.

“The power necessary for different mill parts is:

For each 850lb. stamp, dropping 6 inches 95 times per minute, 1·33 h.p. ” 750 ” ” ” ” 1·18 ” ” 650 ” ” ” ” 1·00 ” For an 8-inch by 10-inch Blake pattern rock-breaker 9·00 ” For a Frue or Triumph vanner, with 220 revolutions per minute,0·50 ” For a 4-feet clean-up pan, making 30 ” ” 1·50 ” For an amalgamating barrel, making 30 ” ” 2·50 ” For a mechanical batea, making 30 ” ” 1·00 ”

The writer has had small practical experience of the working of that excellent hydraulic motor, the Pelton wheel, but if by horse-power in the table given is meant nominal horse-power, it appears to be high. Working with 800 cwt. stamps, 80 blows a minute, 1 h.-p. nominal per stamp will be found sufficient with any good modern engine, which has no further burden than raising the stamps and pumping the feed water. It is always well, however, particularly when providing engine power, to err on the right side, and make provision for more than is absolutely needed for actual battery requirements. This rule applies with equal potency to pumping engines.

TO AVOID LOSS IN CLEANING UP.

The following, is a hint to quartz mill managers with respect to that common source of loss of gold involved in the almost inevitable loss of mercury in cleaning up operations. I have known hundreds of pounds’ worth of gold to be recovered from an old quartz mill site by the simple process of washing up the ground under the floor.

If you cannot afford to floor the whole of the battery with smooth concrete, at all events smoothly concrete the floor of the cleaning-up room, and let the floor slope towards the centre: where a sink is provided. Any lost mercury must thus find its way to the centre, where it will collect and can be panned off from time to time. Of course an underground drain and mercury trap must be provided.

IRON EXTRACTOR.

When using self-feeders, fragments of steel tools are especially liable to get into the battery boxes or other crushing appliance where they sometimes cause great mischief. I believe the following plan would be a practicable remedy for this evil.

By a belt from the cam or counter shaft, cause a powerful electric magnet to extract all magnetic particles; then, by a simple ratchet movement, at intervals withdraw the magnet and drop the adhering fragments into a receptacle by automatically switching off the electric current. A powerful ordinary horse-shoe magnet might probably do just as well, but would require to be re-magnetised from time to time.

TO SILVER COPPER PLATES.

To silver copper plates, that is, to amalgamate them on the face with mercury, is really a most simple operation, though many battery men make a great mystery of it. Indeed, when I first went into a quartz mill the process deemed necessary was not only a very tedious one, but very dirty also.

To amalgamate with silver, in fact, to silver-plate your copper without resort to the electro-plating bath, take any old silver (failing that, silver coin will do, but is more expensive), and dissolve it in somewhat dilute nitric acid, using only just sufficient acid as will effect the purpose. When the crystals have formed, add sufficient clean quick mercury to form a thick pasty amalgam; moderate heat will assist the process. After some hours place the ball of amalgam in a piece of strong new calico and squeeze out any surplus mercury.

About an ounce of silver to the foot of copper is sufficient. To apply it on new plates use somewhat dilute nitric acid applied with a swab to free the surface of the copper from oxides or impurities, then rub the ball of amalgam over the surface, using some little force. It is always well when copper-plates are coated with silver or zinc by means of mercury to let them stand dry for a day or two before using, as the mercury oxidises and the coating metal more closely adheres.

Only the very best copper-plate procurable should be used for battery tables; bad copper will always give trouble, both in the first “curing,” and after treatment. It should not be heavily rolled copper, as the more porous the metal the more easily will the mercury penetrate and amalgamate. I cannot agree that any good is attained by scouring the plates with sand and alkalies, as recommended in some books on the subject; on the contrary, I prefer the opposite mode of treatment, and either face the plates with nitrate of silver and nitrate of mercury, or else with sulphate of zinc and mercury, in the form of what is called zinc amalgam. If mine water, which often contains free sulphuric acid, is being used, the latter plan is preferable.

The copper should be placed smoothly on the wooden table and secured firmly thereto by copper tacks. If the plate should be bent or buckled, it may be flattened by beating it with a heavy hammer, taking care to interpose a piece of inch-thick soft wood between hammer and plate.

To coat with mercury only, procure some nitrate of mercury. This is easily made by placing mercury in a glazed earthenware bowl, pouring somewhat dilute nitric acid on it, and letting it stand till the metallic mercury is changed to a white crystal. Dense reddish-brown fumes will arise, which are injurious if breathed, so the operation should be conducted either in the open air, or where there is a draught.

Now have your silvering solution ready, which is to be somewhat diluted with water, next take two swabs, with handles about 12 inches long, dip the first into a basin containing dilute nitric acid, and rub it rapidly over about a foot of the surface of the plate; the oxide of copper will be absolutely removed, and the surface of the copper rendered pure and bright; then take the other swab, wet with the dilute nitrate of mercury, and pass it over the clean surface, rubbing it well in. Continue this till the whole plate has a coating of mercury. It may be well to go over it more than once. Then turn on the water and wash the plate clean, sprinkle with metallic mercury, rubbing it upwards until the plate will hold no more.

A basin with nitrate of mercury may be kept handy, and the plates touched up from time to time for a few days until they get amalgamated with gold, after which, unless you have much base metal to contend with, they will give no further trouble.

It must be remembered, however, that an excessive use of nitric acid will result in waste of mercury, which will be carried off in a milky stream with the water; and also that it will cause the amalgam to become very hard, and less active in attracting other particles of gold.

If you are treating the plate with nitrate of silver prepared as already mentioned, clean the plate with dilute nitric acid, rub the surface with the ball of amalgam, following with the swab and fairly rubbing in. It will be well to prepare the plate some days before requiring to use it, as a better adhesion of the silver and copper takes place than if mercury is applied at once.

To amalgamate with zinc amalgam, clean the copper plate by means of a swab, with fairly strong sulphuric acid diluted with water; then while wet apply the zinco-mercury amalgam and well rub in. To prepare the zinc amalgam, clip some zinc (the lining of packing cases will do) into small pieces and immerse them in mercury after washing them with a little weak sulphuric acid and water to remove any coating of oxide. When the mercury will absorb no more zinc, squeeze through chamois leather or calico (as for silver amalgam), and well rub in. The plate thus prepared should stand for a few days, dry, before using. If, before amalgamation with gold takes place, oxide of copper or other scum should rise on this plate a little very dilute sulphuric acid will instantly remove it.

Sodium and cyanide of potassium are frequently used in dressing-plates, but the former should be very sparingly employed, as it will often do more harm than good by taking up all sorts of base metals with the amalgam, and so presenting a surface which the gold will pass over without adhering to. Where water is scarce, and is consequently used over and over again, lime may be added to the pulp, or, if lime is not procurable, wood ashes may be used. The effect is two-fold; the lime not only tends to “sweeten” sulphide ores and keep the tables clean, but also causes the water to cleanse itself more quickly of the slimes, which will be more rapidly precipitated. When zinc amalgam is used, alkalies would, of course, be detrimental.

When no other water than that from the mine is available, difficulties often arise owing to the impurities it contains. These are various, but among the most common are the soluble sulphates, and sometimes free sulphuric acid evolved by the oxidisation of metallic sulphides. In the presence of this difficulty, do one of two things: either _utilise_ or _neutralise_. In certain cases, I recommend the former. Some time since I was treating, for gold extraction, material from a mine which was very complex in character. For this ore I coined the term “polysynthetic.” This contained about half a dozen different sulphides. The upper parts of the lode being partially oxidised, free sulphuric acid (H₂SO₄) was evolved. I therefore, following out a former discovery, added a little metallic zinc to the mercury in the boxes and on the plates with excellent results. When the free acid in the ore began to give out in the lower levels I added minute quantities of sulphuric acid to the water from time to time. I have since found, however, that with some water, particularly West Australian, the reaction is so feeble (probably owing to the lime and magnesia present) as to make this mode of treatment unsuitable.

HOW TO MAKE A DOLLY.

I have seen some rather elaborate dollies, intended to be worked with amalgamating tables, but the usual prototype of the quartz mill is set up, more or less, as follows: A tree stump, from 9 in. to a foot diameter, is levelled off smoothly at about 2 ft. from the ground; on this is firmly fixed a circular plate of ½ in. iron, say 9 in. in diameter; a band of ³/₁₆ in. iron, about 8 or 9 in. in height, fits more or less closely round the plate (Fig. 35). This is the battery box. A beam of heavy wood, about 3 in. diameter and 6 ft. long, shod with iron, is vertically suspended, about 9 in. above the stump, from a flexible sapling with just sufficient spring in above the stump, from a flexible sapling with just sufficient spring in it to raise the pestle to the required height. About 2 ft. from the bottom the hanging beam is pierced with an auger hole and a rounded piece of wood, 1½ in. by 18 in., is driven through to serve as a handle for the man who is to do the pounding. His mate breaks the stone to about 2 in. gauge and feeds the box, lifting the ring from time to time to sweep off the triturated gangue, which he screens through a sieve into a pan and washes off, either by means of a cradle or simply by panning. In dollying it generally pays to burn the stone, as so much labour in crushing is thus saved. A couple of small kilns to hold about a ton each dug out of a clay bank will be found to save fuel where firewood is scarce, and will more thoroughly burn the stone and dissipate the base metals, but it must be remembered that gold from burnt stone is liable to become so encrusted with the base metal oxides as to be difficult to amalgamate. Fig. 35A represents another primitive dolly (Plate VI. hand dollying).

ROUGH WINDLASS.

Make two St. Andrew’s crosses with four saplings, the upper angle being shorter than the lower; fix these upright, one at each end of the shaft; stay them together by cross pieces till you have constructed something like a “horse,” such as is used for sawing wood, the crutch being a little over 3 feet high. Select a log for a windlass barrel, about 6 in. diameter and a foot longer than the distance between the supports, as straight as is procurable; cut in it two circular slots about an inch deep by 2 in. wide to fit into the forks; at one end cut a straight slot 2 in. deep across the face. Now get a crooked bough, as nearly the shape of a handle as nature has produced it, and trim it into right angular shape, fit one end into the barrel, and you have a windlass that will pull up many a ton of stuff.

PUDDLER.

This is made by excavating a circular hole about 2 ft. 9 in. deep and, say, 12 ft. in diameter. An outer and inner wall are then constructed of slabs 2 ft. 6 in. in height to ground level, the outer wall being thus 30 ft. and the inner 15 ft. in circumference. The circular space between is floored with smooth hard-wood slabs or boards, and the whole made secure and water-tight. In the middle of the inner enclosure a stout post is planted, to stand a few inches above the wall, and the surrounding space is filled up with clay rammed tight. A strong iron pin is inserted in the centre of the post, on which is fitted a revolving beam, which hangs across the whole circumference of the machine and protrudes a couple of feet or so on each side. To this beam are attached, with short chains, a couple of drags made like V-shaped harrows by driving pieces of rod iron through a heavy frame, shaped as a rectangular triangle (Fig. 36).

To one end of the beam an old horse is attached, who, as he slowly walks round the circular track, causes the harrows and drags to so puddle the washdirt and water in the great wooden enclosure that the clay is gradually disintegrated, and flows off with the water which is from time to time admitted. The clean gravel is then run through a “cradle,” “long Tom,” or “sluice,” and the gold saved. This, of course, is the simplest form of gold mining. In the great alluvial mines other and more intricate appliances are used, but the principle of extraction is the same.

A MAKESHIFT PUMP.

To make a temporary small “draw-lift” pump, which will work down to a hundred feet or more if required, take a large size common suction Douglas pump, and, after removing the top and the handle, fix the pump as close to the highest level of the water in the shaft as can be arranged. Now make a square water-tight wooden column of slightly greater capacity than the suction pipe, fix this to the top of the pump, and by means of wooden rods, work the whole from the surface, using either a longer levered handle or, with a little ingenuity, horse-power. If you can get it the iron downpipe used to carry the water from the guttering of houses is more easily adapted for the pipe column; then, also, iron pump rods can be used, but I have raised water between 60 and 70 feet with a large size Douglas pump provided only with a wooden column and rods.

SQUEEZING AMALGAM.

For squeezing amalgam, strong calico, not too coarse, previously soaked in clean water, is quite as good as ordinary chamois leather. Some gold is fine enough to escape through either.

MERCURY EXTRACTOR.

The mercury extractor or amalgam separator (Fig. 38) is a machine which is very simple in construction, and is stated to most efficient in extracting quicksilver from amalgam, as it requires but from two to three minutes to extract the bulk of the mercury from one hundred pounds of amalgam, leaving the amalgam drier than when strained in the ordinary way by squeezing through chamois leather or calico. The principle is that of the De Laval cream separator--_i.e._, rapid centrifugal motion. The appliance is easily put together, and as easily taken apart. The cylinder is made of steel, and is run at a very high rate of speed.

The general construction of the appliance is as follows: The casing or receiver is a steel cylinder, which has a pivot at the bottom to receive the step for an upright hollow shaft, to which a second cylinder of smaller diameter is attached. The second cylinder is perforated, and a fine wire cloth is inserted. The mercury, after passing through the cloth, is discharged through the perforations. When the machine is revolved at great speed, the mercury is forced into the outside cylinder, leaving the amalgam, which has been first placed in a calico or canvas bag, in a much drier state than it could be strained by hand. While not prepared to endorse absolutely all that is claimed for this appliance, I consider that it has mechanical probability on its side, and that where large quantities of amalgam have to be treated it will be found useful and effective.

SLUICE PLATES.

I am indebted to Mr. F. W. Drake for the following account of sluice plates, which I have never tried, but think the device worth attention:

“An addition has been made to the gold-saving appliances by the placing of what are called in America, ‘sluice plates’ below the ordinary table. The pulp now flows over an amalgamating surface, 14 ft. long by 4 ft. wide, sloping 1½ in. to the foot, and is then contracted into a copper-plated sluice 15 ft. long by 14 in. wide, having a fall of 1 in. to the foot. Our mill manager (Mr. G. C. Knapp), advocated these sluice plates for a long time before I would consent to a trial. I contended that as we got little or no amalgam from the lower end of our table plates, there was no gold going away capable of being recovered by copper plates; and even if it were, narrow sluice plates were a step in the wrong direction. If anything, the amalgamating surface should be widened to give the particles of gold a better chance to settle. His argument was that the conditions should be changed; by narrowing the stream and giving it less fall, gold, which was incapable of amalgamation on the wide plates, would be saved. We finally put one in, and it proved so successful that we now have one at the end of each table. The percentage recovered on the sluice plates, of the total yield, varies, and has been as follows:--October, 9·1 per cent.; November, 6·9 per cent.; December, 6·4 per cent.; January, 4·3 per cent.; February, 9·3 per cent.”

MEASURING INACCESSIBLE DISTANCES.

To ascertain the width of a difficult gorge, a deep river, or treacherous swamp without crossing and measuring, sight a conspicuous object at the edge of the bank on the farther side; then as nearly opposite and square as possible plant a stake about five feet high, walk along the nearer margin to what you guess to be half the distance across (exactitude in this respect is not material to the result), there plant another stake, and continuing in a straight line put in a third. The stakes must be equal distances apart and as nearly as possible at a right angle to the first line. Now, carrying in hand a fourth stake, strike a line inland at right angles to the base and as soon as sighting over the fourth stake, you can get the fourth and second stakes and the object on the opposite shore in line your problem is complete. The distance between No. 4 and No. 3 stakes is the same as that between No. 1 and the opposite bank (Fig. 39).

TO SET OUT A RIGHT ANGLE WITH A TAPE.

Measure 40 ft. on the line to which you wish to run at right angles, and put pegs at A and B (Fig. 40); then, with the end of the tape held carefully at A, take 80 ft., and have the 80 ft. mark held at B. Take the 50 ft. mark and pull from A and B until the tape lies straight and even, you will then have the point C perpendicular to AB. Continue straight lines by sighting over two sticks in the well-known way.

_Another Method._--Stick a pin in each corner of a square board (Fig. 41), and look diagonally across them, first in the direction of the line to which you wish to run at right angles, and then for the new line sight across the other two pins.

A SIMPLE LEVELLING INSTRUMENT.

Fasten a common carpenter’s square in a slit to the top of a stake by means of a screw, and then tie a plumb-line at the angle so that it may hang along the short arm, when the plumb-line hangs vertically and sights may be taken over it. A carpenter’s spirit-level set on an adjustable stand will do as well. The other arm will then be a level (Fig. 42).

Another very simple, but effective, device for finding a level line is by means of a triangle of wood made of half-inch boards from 9 to 12 ft. long (Fig. 43). To make the legs level, set the triangle up on fairly level ground, suspend a plummet from the top and mark on the cross-piece where the line touches it. Then reverse the triangle, end for end, exactly, and mark the new line the plumb-line makes. Now make a new mark exactly half way between the two, and when the plumb-line coincides with this, the two legs are standing on level ground. For short water races this is a very handy method of laying out a level line.

TO MEASURE THE HEIGHT OF A STANDING TREE.

Take a stake about your own height, and walking from the butt of the tree to what you judge to be the height of the timber portion you want, drive your stake into the ground till the top is level with your eyes; now lie straight out on your back, placing your feet against the stake, and sight a point on the tree (see Fig. 44). AB equals BC. If BC is, say, 40 ft., that will be the height of your “stick of timber.” Thus, much labour may be saved in felling trees the timber portion of which may afterwards be found to be too short for your purpose.

LEVELLING BY ANEROID BAROMETER (Fig. 45).

This should be used more for ascertaining relatively large differences in altitudes than for purposes where any great nicety is required. For hills under 2000 ft., the following rule will give a very close approximation, and is easily remembered, because 55°, the assumed temperature, agrees with 55°, the significant figures in the 55,000 factor, while the fractional correction contains _two fours_.

Observe the altitudes and also the temperatures on the Fahrenheit thermometer at top and bottom respectively, of the hill, and take the mean between them. Let _B_ represent the mean altitude and _b_ the mean temperature. Then 55000 × (B-b / B + b) = height of the hill in feet for the temperature of 55°. Add 1/440 of this result for every degree the mean temperature exceeds 55°; or subtract as much for every degree below 55°.

TO DETERMINE HEIGHTS OF OBJECTS.

_By Shadows._

1. Set up vertically a stick of known length, and measure the length of its shadow upon a horizontal or other plane; measure also the length of the shadow thrown by the object whose height is required. Then it will be:--As the length of the stick’s shadow is to the length of the stick itself, so is the length of the shadow of the object to the object’s height.

_By Reflection._

Place a vessel of water upon the ground and recede from it until you see the top of the object reflected from the surface of the water. Then it will be:--As your horizontal distance from the point of reflection is to the height of your eye above the reflecting surface, so is the horizontal distance of the foot of the object from the vessel to its altitude above the said surface.

_Instrumentally._

Read the vertical angle, and multiply its natural tangent by the distance between instrument and foot of object; the result is the height.

When much accuracy is not required vertical angles can be measured by means of a quadrant of simple construction, represented in Fig. 46. The arc AB is a quadrant, graduated in degrees from B to A; C, the point from which the plummet P is suspended, being the centre of the quadrant.

_When_ the sights AC are directed towards any object, S, the degrees in the arc, BP, are the measure of the angle of elevation, SAD, of the object.

TO FIND THE DEPTH OF A SHAFT.

_Rule_:--Square the number of seconds a stone takes to reach the bottom and multiply by 16.

Thus, if a stone takes 5 seconds to fall to the bottom of a shaft--

5² = 25; and 25 × 16 = 400 feet, the required depth of shaft.

DESCRIPTION OF PLAN FOR RE-USING WATER.

Where water is scarce it may be necessary to use it repeatedly. In a case of this kind in Egypt, the Arab miners have adopted an ingenious method, which is shown in Fig. 47, and may be adapted to almost any set of conditions. At _a_ is a sump or water-pit; _b_ is an inclined plane on which the mineral is washed and whence the water escapes into a tank _c_; _d_ is a conduit for taking the water back to _a_; _e_ is a conduit or lever pump for raising the water. A certain amount of filtration could easily be managed during the passage from _c_ to _a_.

COOLING COMPOUND FOR HEATED BEARINGS.

Mercurial ointment mixed with black cylinder oil and applied every quarter of an hour, or as often as expedient. The following is also recommended as a good cooling compound for heavy bearings:--Tallow 2 lb., plumbago 6 oz., sugar of lead 4 oz. Melt the tallow with gentle heat and add the other ingredients, stirring until cold.

CLEANING GREASY PLUMMER BLOCKS.

When, through carelessness or unpreventable causes, plummer blocks and other detachable portions of machinery become clogged with sticky deposits of grease and impurities, a simple mode of cleansing the same is to take about 1000 parts by weight of boiling water, to which add about 10 or 15 parts of ordinary washing soda. Keep the water on the boil and place therein the portions of the machine that are to be cleaned; this treatment has the effect of quickly loosening all grease, oil, and dirt, after which the metal is thoroughly washed and dried. The action of the lye is to form with the grease a soap soluble in water. To prevent lubricating oil hardening upon the parts of the machinery when in use, add a third part of kerosene.

PREVENTING SCALING AND PRIMING IN BOILERS.

Graphite “black-lead” added to the water in a boiler prevents scaling and priming. My method is to paint the inside of the boiler with a good coat of graphite mixed with water to the consistency of thin gruel, and let it stand till dry. It will not be amiss to give a second coat before getting up steam. Even if slight scaling has already taken place, the graphite particles will penetrate and the scale come away gradually.

CLEARING SCALE-STOPPED PIPES.

Where the water contains a large amount of mineral in solution, the pipes, particularly the small ones, inch to two inch, quickly become useless because of the rapid deposition of scale. I have seen in West Australia tons of small pipes thrown on to the scrap heap after a few months use, because of this difficulty. The treatment now indicated, which is my own invention, will make such pipes as good as new at small expense. Have a brick trough a little longer than your pipe. In this put a fire of wood, charcoal, coke, or a mixture of such fuel. Lay the pipes, a few at a time, in this. Heat slowly to cherry red. Then with pinchers suddenly immerse in a second trough of cold water, supporting one end above the water level. Most of the scale or incrustation will be violently ejected. With a long pipe, if the heat has not been regular, some may still adhere. Then usually tapping with a hammer will detach it. If not, a second heating and immersion will do so, leaving the interior as clean as when made. It is hardly necessary to add that ’tis best to stand clear of the ends when the explosion takes place.

AN EXCELLENT ANTI-FRICTION COMPOUND.

For use on cams and stamper shanks, which will be harmless should it drop into the mortar or stamper boxes, is graphite (black-lead) and soft soap. When the guides are wooden, the soft soap need not be added; graphite “black-lead” made into a paste with water will act admirably.

TO CLEAN BRASS.

Oxalic acid 1 oz., rotten stone 6 oz., powdered gum arabic ½ oz., sweet oil 1 oz. Rub on with a piece of rag.

A SOLVENT FOR RUST.

It is often very difficult, and sometimes impossible, to remove rust from articles made of iron. Those which are very thickly coated are most easily cleaned by being immersed in a nearly saturated solution of chloride of tin. The length of time they remain in this bath is determined by the thickness of the coating of rust. Generally from twelve to twenty-four hours is long enough.

TO PROTECT IRON AND STEEL FROM RUST.

The following method is but little known, although it deserves preference over many others. Add 7 oz. of quicklime to 1¾ pints of cold water. Let the mixture stand until the supernatant fluid is entirely clear. Then pour this off, and mix with it enough olive oil to form a thick cream, or rather to the consistency of melted and recongealed butter. Grease the articles of iron or steel with this compound, and then wrap them up in paper, or if this cannot be done, apply the mixture somewhat more thickly.

TO KEEP MACHINERY FROM RUSTING.

Take 1 oz. of camphor, dissolve it in 1 lb. of melted lard; mix with it (after removing the scum) as much fine graphite as will give it an iron colour; clean the machinery, and smear it with this mixture. After twenty-four hours rub off and clean with soft, linen cloth. This mixture will keep machinery clean for months under ordinary circumstances.

FIRE-LUTE.

An excellent fire-lute is made of eight parts sharp sand, two parts good clay, and one part horse-dung; mix and temper like mortar.

ROPE-SPLICING.

A short splice is made by unlaying the ends of two pieces of rope to a sufficient length, then interlaying them as in Fig. 48 (upper cut), draw them close and push the strands of one under the strands of the other several times as shown in the lower cut.

This splice makes a thick lump on the rope and is only used for slings, block-straps, cables, &c.

APPENDIX

(_SELECTED DATA FOR MINING MEN_)

TO FIND LOST PART OF VEIN

Zimmermann’s rule for finding the lost part of a vein on the other side of a vein, is as follows:--

Lay down upon paper the line of strike of lode and the line of strike of the fault (cross-course), and by construction ascertain the horizontal projection of the line of their intersection; from the point where the cross-course was struck by the lode, draw a line at right angles to the strike of the former and directed to its opposite wall. Notice on which side of the line of intersection this perpendicular falls, and after cutting through the cross-course, seek the “heaved” part of the lode on that side.

Thus let AB (Fig. 49) represent, at any depth, the line of strike of a fault or cross-course dipping east, and CD the line of strike of a lode dipping south, and we will suppose that in driving from C to D in a westerly direction, the fault has been met with at D. Knowing the dip of the lode and that of the fault, it is easy to lay down on any given scale, A′B′ and C′D′, the lines of strike of the fault and lode respectively at a certain depth, say 10 fathoms, below AB. The point D″, where A′B′ and C′D′ meet, is one point of the line of intersection. Join D and D″, and prolong on both sides. The line MN represents the horizontal projection of the line of intersection of the two planes. At D erect DE at right angles and directed towards the opposite wall of the fault. As DE falls south of MN, the miner, after cutting through the fault, would drive in a southerly direction and eventually strike the lode again at F. It will be at once understood that if the miner were following the lode from _b_ to F, the perpendicular would lie to the north of the line of intersection, and following the rule, he would drive in that direction, after cutting through the fault. When several faults in succession dislocate a lode, very great complications may arise.

THE CALCULATION OF ORE RESERVES.[4]

Having finished the survey of a metalliferous mine, the surveyor is sometimes called upon to calculate the quantity of ore reserves in that mine. Various methods are employed for this purpose.

[4] Bennett H. Brough’s “Treatise on Mine Surveying,” sixth edition, p. 165.

Indeed, different surveyors will not agree within wide limits as to the amount of ore reserves in the same mine. Sometimes the amount of ore in sight will be considered to be a rectangular block, limited by the outcrop of the vein, the depth of the shaft, and the extreme points of the levels, diminished by the amount extracted. Other surveyors would avoid so excessive an amount, and take but one-third of that amount.

The following method is recommended by Mr. J. G. Murphy, an experienced American mining engineer, as the fairest and most trustworthy:--

Let it be required to calculate the ore reserves in a mine opened up on a vein with a mean cross section of 6 feet; a cubic foot of the vein matter in place weighing 150 lb. The ore stopes are generally very irregular. In this case, however, it may be supposed that the stope faces are 11 feet apart and 8 feet high. There is an inclined shaft, 10 feet by 6 feet, following the dip of the vein, and six levels, each 7 feet by 6 feet, 100 feet apart. The lengths of the levels are--

I. 200 feet west 150 feet east. II. 160 ” 100 ” III. 120 ” 400 ” IV. 100 feet west 140 feet east. V. 165 ” 180 ” VI. 350 ” 150 ”

The longest level west is 350 feet, and the shortest 100 feet.

Assuming the bounding line of the area of available ore to be at a distance west of the shaft--

100 + (350-100) = 225 feet --------- 2

If the longest level east is 400 feet, and the shortest 100 feet, the bounding line in this direction, calculated in a similar way, will be at a distance of 250 feet from the shaft.

The inclined shaft has opened up the vein for 670 feet. Deducting, say, 15 feet for the irregularity of the surface, the quantity of ore in sight will be a rectangular block 655 feet deep, 225 + 250, or 475 feet long and 6 feet wide, that is 1,866,750 cubic feet.

From this quantity, however, must be deducted the quantity of ore extracted, namely:--

Cubic Feet.

Inclined shaft 665 × 10 × 6 = 39,900 Level I. 350 × 7 × 6 = 14,700 ” II. 260 × 7 × 6 = 10,920 ” III. 520 × 7 × 6 = 21,840 ” IV. 240 × 7 × 6 = 10,080 ” V. 345 × 7 × 6 = 14,490 ” VI. 500 × 7 × 6 = 21,000 ” I. Stoped east (rough estimate) 3,400 ” I. ” west 6,500 ” II. ” west 7,000 ” III. ” east 20,000 ” VI. ” west 12,000 -------- Total 181,530 Or in round numbers 182,000

This quantity, deducted from 1,866,750 cubic feet, leave 1,684,750 cubic feet. Divided by 13½, the number of cubic feet required for a ton, this gives 124,797 tons of ore in sight.

The quantity of ore discovered in a mine may be estimated from its specific gravity and the average size of the vein. The specific gravity of the ore, with that of water taken at 1000 for standard is equal to the number of ounces in a cubic foot. Great caution is necessary to determine the proportion of the vein which may be considered solid ore. A vein 6 feet square and 1 inch thick, contains 3 cubic feet, therefore, in order to find the number of cubic feet per square fathom of a vein, it is merely necessary to multiply the thickness in inches by three.

The following example illustrates the method of finding the weight of any ore per square fathom in a vein. What quantity of galena will be produced per square fathom from a mineral vein 6 inches in width? One quarter of the vein consists of galena, the remainder of zinc-blende. One-twentieth must be allowed for cavities in the vein. The specific gravity of galena is 7·5, and a cubic foot of water weighs 1000 ounces; therefore a cubic foot of galena weighs 7500 ounces.

The vein being 6 inches thick, there are 18 cubic feet in a square fathom. One quarter of that amount, or 4·5 cubic feet, consists of galena. The weight of galena in ounces is therefore:

7500 × 4·5 = 33,750 = 2109·375 lb. From this one-twentieth or 105·468 lb. -------------- must be deducted, leaving 2003·907 lb.

or 17 cwt. 3 qr. 15 lb. as the weight of lead ore per square fathom.

ESTIMATING ORE VALUES.

In testing a gold mine with a view to purchase, it should be remembered that as a rule the intersections of leaders or small veins with the main ore body are usually the richest portions of the lode. This the experienced prospector knows, and generally his shafts and cuttings are made at such points. For the ordinary mining investor, when inspecting with a view to purchase, these are places to avoid if endeavouring to form a correct estimate of the value of the ore in bulk. Take samples across the lode from place to place, break down and bag personally, and mark bags. Test the rich portions separately and average, estimating quantity of both.

CALIFORNIA PUMP.

Any handy man or rough bush carpenter can make a California Pump. The prospectors in the illustration (Plate VII.) are using a home-made contrivance, which is quite effective for raising water from shallow depths for “long tom,” or ground sluicing--a wooden frame-work and open wooden wheel with handle. Over the wheel is run a belt of canvas, say, six inches wide, with wood stops about a foot apart--a long sloping box, dipping into the water, up which the stopped belt travels--and you have a California Pump which, if not a highly scientific device, is at least very serviceable.

HYDRAULICS.

_General Data Regarding Water._

An imperial gallon of water weighs, at 62° F., 10 lbs. avoirdupois. Gallons × ·1606 = cubic feet. Cubic feet × 6·288 = number of gallons.

Gallons × 277·46 = cubic inches. Cubic inches × 0·003604 = gallons. Cubic feet of water × 62·28 = number of pounds weight. Pounds of water × 0·0166 = cubic feet. Gallons of water × 0·004464 = number of tons. Tons of water × 224 = gallons of water. Cubic feet of water × 0·0278 = number of tons. Tons of water × 35·97 = cubic feet of water.

A pipe 1 yard long holds approximately (actually, 1·52 per cent. less) as many pounds of water as the square of its diameter in inches; thus a 6-inch pipe holds approximately 36 lbs. of water in each yard length.

_Water Pressure._

Ten feet head of water gives a pressure of 4½ lbs. per square inch approximately.

If H = head of water in feet, P = pounds pressure per square inch:

H = P × 2·311 P = H × ·4326

_Horse-power required to Pump Water._--One h.-p. indicated will raise about 3000 gallons of water per hour 50 feet high.

To pump 1 gallon of water per minute against a pressure of 4 lb. per square inch, requires:

p × ·0007 H.-P.

BORING.

Rock is bored with jumpers of 10 lb. to 18 lb., used alone, or with boring bars and hammer. The former are more effective, but can only be used perpendicularly, or nearly so, and with rock of moderate hardness; they require more skill.

18 lb. hammers are used for 3 in. boring bars. 16 lb. ” ” 2½ in. ” 14 lb. ” ” 2 & 1¾ in. ” 5-7 lb. ” ” 1 in. ”

The boring bars may be made of 1-1/8-inch bar iron of various lengths, with steel bits up to 3 inches. A bit should bore from 18 feet to 24 feet with each steeling, and requires to be sharpened once for every foot bored.

3 men with a 3-inch bar should bore 4 feet. 3 ” ” 2½ ” ” ” 6 ” 3 ” ” 2 ” ” ” 8 ” 3 ” ” 1¾ ” ” ” 12 ” 2 ” ” 1 ” ” ” 8 ” per day of 10 hours in hard granite.

POWER, ETC., REQUIRED TO WORK ROCK DRILLS.

+-----+----------+----------+--------+---------------+ | | Diameter | Diameter | | No. of | |H.-P.| of Air | of Steam | Stroke.| 3-inch Drills | | | Cylinder.| Cylinder.| | driven. | +-----+----------+----------+--------+---------------| | | Inches. | Inches. | Inches.| | | 6 | 8 | 8½ | 12 | 1 | | 10 | 10 | 10½ | 16 | 2 | | 14 | 12 | 12¼ | 22 | 3 | | 16 | 13 | 13 | 24 | 4 | | 20 | 14½ | 14½ | 28 | 5 | | 30 | 17½ | 17½ | 36 | 8 | | 40 | 20 | 20 | 36 | 11 | | 60 | 22 | 24 | 60 | 15 | +-----+----------+----------+--------+---------------+

POWER REQUIRED TO WORK DOUBLE STEAM AND AIR CYLINDERS.

+------+----------+------------+---------+---------------+ | | Diameter | Diameter of| | No. of 3-inch | | H.-P.| of Air | Steam | Stroke. | Rock Drills | | | Cylinder.| Cylinder. | | driven. | +------+----------+------------+---------+---------------+ | | Inches. | Inches. | Inches.| | | 28 | 12 | 12 | 22 | 7 | | 32 | 13 | 13 | 24 | 8 | | 40 | 14½ | 14½ | 28 | 10 | | 60 | 17½ | 17½ | 36 | 15 | | 80 | 20 | 20 | 36 | 22 | | 120 | 22 | 24 | 60 | 30 | +------+----------+------------+---------+---------------+

DURABILITY OF ROPES.

The average duration of flat, wire ropes is usually taken at one year, and that of round ropes at half a year.

DIAMOND DRILLING.

This drill is applicable to sinking a borehole for prospecting for minerals or water, shafts, &c., or blasting under water.

It consists of a circular row of “carbonados,” a species of diamond, set in a circular steel ring. This is attached to a hollow steel tube which is kept rotating at about 250 revolutions per minute, pressed forward by a force varying from 400 to 800 lb. according to the nature of the rock. Water is supplied through the tube which washes out the _débris_ and cools the diamonds.

Granite and the hardest limestones are penetrated at the rate of 2 to 3 inches per minute, sandstones 4 inches, quartz 1 inch.

The diamond drill is not effective in soft strata such as clay, sand, and alluvial deposits.

Boreholes have been made at the following rates:

_In Ironstone formation_:

A depth of 902 feet in 54 working days. 641 ” 48 ” 434 ” 54 ” 640 ” 60 ” Or an average of 12 feet a day.

_In Coal measures_:

A depth of 1008 feet in 146 days 802 ” 168 ” 700 ” 48 ” 558 ” 42 ” Or an average of 7½ feet a day.

TIMBER.

=To find Solidity of Round Timber.=

_When all dimensions are in feet_: Length × (¼ mean girth)² = cubic feet.

_When length in feet_, _girth in inches_: Length × (¼ mean girth) ÷ 144 = cubic feet.

_When all dimensions are in inches_: Length × (¼ mean girth)² ÷ 1728 = cubic feet.

=To find Solidity of Square Timber.=

_When all dimensions are in feet_: Length × breadth × depth = cubic feet.

_When one dimension is in inches_: Length × breadth × depth ÷ 12 = cubic feet.

_When two dimensions are in inches_: Length × breadth × depth ÷ 144 = cubic feet.

For board measure, depth always equal 1 inch.

To find surface in square feet, proceed as per rules for solidity of square timber.

LAYING OUT OF AREAS.

1. _In Squares._--Extract the square root of the desired content, reduced to square chains (ten square chains equal one acre). The result will be the length of the required side in chains.

Thus if we wish to find the side of a square block containing 25 acres, we first reduce the acres to square chains: 25 × 10 = 250, the square root of which is 15·81, or 15 chains 81 links; the side required.

By reference to the tables of square roots on page 189, the required sides of square block for a large number of acres can be read off at once.

_One acre_ laid out as a square must have its side made 316¼ links, or 208-71/100 feet, or 69-57/100 yards, 70 paces being a near approximation.

2. _In Rectangles._--Divide the content by the length or breadth, according to which factor is known, and the result will be the required side.

Thus 5 acres, or 50 square chains, if 10 chains long, will require to be 5 chains wide.

If the content only is given, and the length is to be a certain number of times the breadth, the content in square chains divided by the ratio of the length to the breadth, and the square root of the quotient, will give the length of the shorter side. Thus, if we wish to lay out 72 acres as a rectangle twice as long as broad: 72 acres = 720 square chains, divided by 2, the ratio given, = 360, the square root of which is 18·97 chains, the length of the shorter side. The length of the other side is therefore 18·97 × 2 = 37·94 chains, or 3794 links.

MENSURATION.

=TO FIND THE AREA OF A TRIANGLE WHEN THE BASE AND PERPENDICULAR HEIGHT ARE GIVEN=: Multiply the base by half the height, or _vice versâ_.

=TO FIND THE AREA OF A TRIANGLE WHEN THE THREE SIDES ARE GIVEN=: Take half the sum of the sides, subtract each severally from this sum, then multiply this and the three remainders together, and take the square root for the area.

=TO FIND THE AREA OF A RECTANGULAR FIGURE=: Multiply the length by the breadth, the product will be the area.

=TO FIND THE AREA OF A TRAPEZOID=: Multiply half the sum of the two parallel sides by the distance between them.

=TO FIND THE AREA OF A PARALLELOGRAM WHOSE ANGLES ARE NOT RIGHT ANGLES=: Multiply the length of any one of the sides by the perpendicular.

=TO FIND THE AREA OF A TRAPEZIUM=: Divide it into two triangles and find the areas of the latter by the first rule.

=TO FIND THE AREA OF AN IRREGULAR POLYGON=: Divide the polygon into triangles and find the area of the latter.

=TO FIND THE AREA OF AN IRREGULAR FIGURE=: Draw the figure on fine cardboard or thin sheet metal, cut the same carefully out and weigh with an accurate balance. Then this weight, compared with the weight of a piece of the cardboard or metal of a definite size, say one square inch, gives at once the area required.

MINE SURVEYING PROBLEMS.

It would be futile to profess, in the limits of a small work of this kind, to instruct the beginner fully in the principles and practice of mine surveying, especially as the most elaborate treatise can only be of service when some actual practical experience and knowledge of instruments have been obtained.

For an exhaustive and well-arranged work on the subject, Brough’s “Treatise on Mine Surveying” can be strongly recommended, and should be carefully studied by all wishing to learn the best methods of accomplishing the accurate results that any mine-surveying worth the name demands.

The following methods of connecting underground and surface work are therefore addressed to such as are thoroughly acquainted with a dial and the method of traversing.

1. =TO FIND WHERE A SHAFT SHOULD BE SUNK TO CONNECT WITH ANY PART OF THE UNDERGROUND WORKINGS.=

Should the mine be one opened by an adit, there is no difficulty in doing this, as the dial can be set up at the mouth and a sight taken to a light; this can then, by means of the vertical arc, be prolonged up the hill, and the remaining bearings and distances are then easily laid down to the desired point. When a starting-point has been obtained, the chief difficulty in these cases has been overcome. If a single shaft is the only connection to the underground workings, the magnetic bearing of the first line at bottom must first be carefully ascertained, and the position of the first station brought to the surface by means of a plumb-line, made of copper wire preferably, the plummet being put into a dish of water to steady it. The dial is then set exactly over the end of the line at the surface, and the first bearing and distance laid off.

Should it be impossible to set the instrument over the point at surface, a spot must be found by trial outside the shaft which is in the correct course. The dial is set up in the supposed direction of the line and repeated sights taken to the first point till the instrument and it are exactly in the required line, when the length of the first line can be measured along it, and the new lines proceeded with.

As local attraction frequently affects the needle at the bottom of the shaft, and so vitiates the surface survey that depends on its swinging the same at both points, a method of dispensing with the needle must be resorted to. This is the suspension of two plumb-lines from opposite sides of the shaft, the plummets hanging exactly over as much of the first underground line as the width of the shaft will allow.

The two plummet lines at surface then give the direction, and by trial the dial must be put exactly in line with them in order to prolong it correctly.

If there are two or more shafts sunk on the workings, it will be an easy matter to ascertain if the needle can be depended on for laying out any further surface work, as the underground survey connecting the shafts can be laid down on the surface, or the direct bearing and distance calculated, when its correctness is tested by the terminating point of the survey.

2. =TO FIND DEPTH OF SHAFT AT ANY POINT, TO CUT A VEIN WHOSE DIP IS KNOWN.=

RULE:--Multiply natural tangent of angle of dip C (Fig. 50.) by the distance from outcrop to proposed shaft AC. The result is the depth required, AB.

=_By Protractor and Scale._=--Rule on paper a line AC of the required distance, then at C set off the angle of dip and draw AB at right angles to AC. Then scale off AB = depth of shafts.

3. =GIVEN DEPTH OF SHAFT AND ANGLE OF DIP TO FIND WHERE IT OUTCROPS.= --Then AC = AB × natural tangent of angle ABC. Or by scale and protractor by inspection.

4. =GIVEN DEPTH OF SHAFT AB AND DIP OF VEIN ANGLE CB TO FIND DISTANCE BC BETWEEN BOTTOM OF SHAFT AND OUTCROP.=--BC = AC × natural sine ACB. Or by scale and protractor by inspection.

RAINFALL.

One inch of rain = 22,680 gallons, or 102·35 tons of water per acre.

NOTES ON BELTING.

_Co-efficient_ of friction between ordinary leather belting and cast-iron pulleys or drums = ·423. Ultimate strength of ordinary leather belting = 3086 lb. per square inch. Belts vary from ³/₁₆ in. to ¼ in. thick, average ⁷/₃₂ in.

_Power of Single Leather Belts._

To calculate the power of single leather belts, the following formula may be used: Let HP = actual horse-power. W = width of belt. F = driving force. T = working tension from 70 to 150 lb. V = velocity of belt in feet per minute.

Then F = (W × T)/2. HP = V × F/33,000. W = 33,000 × HP/F × V.

=EXAMPLE:=--A 10-inch belt running 2500 feet per minute, what horse-power will it transmit? Assuming the working tension to be 100 lb.,

F = (10 × 100)/2 = 500. HP = (25,000 × 500)/33,000 = 378 horse-power.

Nystrom gives this rule:--HP = (V × F)/550. V = velocity of belt in feet per second. F = force in pounds transmitted by belt.

The first rule gives good practical results where there is no great inequality in the diameter of the pulleys.

_Double Belts_ transmit 1½ times as much as single belts.

_Splicing Belts._

+----+-----+-----+-------+--------+------------+ Width of Belts. | 1 | 2 | 3 | 3 to 6| 6 to 8 | above 8 in.| Lap in inches . | 2 | 4½ | 5½ | 6 | 8 | 10 | +----+-----+-----+-------+--------+------------+

_Rules for Double Leather Belting._

A = covered area of driven pulley in square inches.

V = speed of belt in feet per minute.

H = indicated horse-power.

W = width in inches.

H = AV/66,000 A = (66,000 H)/V. W = A/L, where L = length of belt on driven pulley in inches.

Another authority simply says H = {70 to 80} × (WV)/33,000

And a third says W = (36,000 H)/(6VL), where L is here in feet.

Evan Leigh’s rule is W = (66,000 × IHP)/(L × V).

L = length of arc of contact upon smaller pulley in inches.

V = velocity of rim in feet per minute.

_A belt_ transmits its motion solely through frictional contact with the surfaces of the pulley. The lower side of the belt should be made the driving side when possible, as the arc of contact is thereby increased by the sagging of the following side. Increase of power will be obtained by increasing the size of pulleys, the same ratio being retained. Wide belts are less effective per unit of sectional area than narrow belts. Long belts are more effective than short ones. The proportion between the diameters of two pulleys working together should not exceed six to one. Convexity of pulleys to receive belt = ½ inch per foot wide. The width of pulley should equal 1·2 times width of belt.

_Speed of Belts._

Belts have been employed running over 5000 feet per minute. Nothing, however, is gained by running belts much over 4000 feet per minute. About 3500 feet per minute for main belts agrees with good practice; lathe belts from 1500 to 2000 feet per minute. The life of a belt may be prolonged and its driving powers increased by keeping it in good working order. To ensure this it should be dressed on the back with castor oil every few weeks, more or less according the dryness of the _atmosphere_ in which it works.

WEIGHT AND BULK OF MATERIALS.

The weight of a cubic foot of any material is its specific gravity multiplied by 62·425, or the weight of a cubic foot of water in pounds. To find the specific gravity of a stone, divide its weight in air by loss of weight in water of temperature of 60° F. = specific gravity.

Thus:

Quartz crystal weighs in air 293·7 grains. ” ” ” water 180·1 ” ----- Loss in weight 113·6 ”

Then:

293·7 / 113·6 = 2·59 = Specific gravity of quartz.

One ton of quartz when solid occupies 13 cubic feet, but when broken, about 20. Rocks when solid, as compared to the same when broken, usually increase in volume in the ratio of 1 to 1·5 or 1 to 1·18, the increase depending on size and form of fragments.

A dwt. of gold in a cwt. of ore = 1 oz. of gold per ton of ore.

For approximate calculation a grain of gold = two pence, and a dwt., four shillings.

In the following table of the chemical elements the standard of sp. gr. is hydrogen for the gaseous elements (hydrogen, oxygen, &c.) and water for the others.

THE CHEMICAL ELEMENTS, THEIR SYMBOLS, EQUIVALENTS, AND SPECIFIC GRAVITIES.

+----------------------+---------+--------+-----------+ | Name. | Symbol. | Atomic | Specific | | | | Weight.| Gravity. | +----------------------+---------+--------+-----------+ | Aluminium | Al | 27·5 | 2·56 | | Antimony | Sb | 122·0 | 6·70 | | Arsenic | As | 75·0 | 5·7 | | Barium | Ba | 137·0 | 4·00 | | Bismuth | Bi | 210·0 | 9·7 | | Boron | B | 11·0 | 2·63 | | Bromine | Br | 80·0 | 5·54 | | Cadmium | Cd | 112·0 | 8·60 | | Caesium | Cs | 133·0 | 1·88 | | Calcium | Ca | 40·0 | 1·58 | | Carbon | C | 12·0 | 3·50 | | Cerium | Ce | 92·0 | 6·68 | | Chlorine | Cl | 35·5 | 2·45 | | Chromium | Cr | 52·5 | 6·81 | | Cobalt | Co | 58·8 | 7·7 | | Columbium | Cb | 184·8 | 6·00 | | Copper | Cu | 63·5 | 8·96 | | Didymium | Di | 96·0 | 6·54 | | Erbium | E | 112·6 | -- | | Fluorine | F | 19·0 | 1·32 | | Gallium | Ga | 69·9 | 5·9 | | Glucinum | Gl | 9·5 | 2·1 | | Gold (Aurum) | Au | 196·7 | 19·3 | | Hydrogen | H | 1·0 | 0·069 | | Indium | In | 113·4 | 7·4 | | Iodine | I | 127·0 | 4·94 | | Iridium | Ir | 198·0 | 21·15 | | Iron (Ferrum) | Fe | 56·0 | 7·79 | | Lanthanum | La | 90·2 | 11·37 | | Lead (Plumbum) | Pb | 207·0 | 11·44 | | Lithium | Li | 7·0 | 0·59 | | Magnesium | Mg | 24·0 | 1·75 | | Manganese | Mn | 55·0 | 8·01 | | Mercury (Hydrargyrum)| Hg | 200·0 | 13·59 | | Molybdenum | Mb | 96·0 | 8·60 | | Nickel | Ni | 58·8 | 8·60 | | Niobium | Nb | 94·0 | 6·27 | | Nitrogen | N | 14·0 | 0·972 | | Osmium | Os | 199·0 | 21·40 | | Oxygen | O | 16·0 | 1·105 | | Palladium | Pd | 106·5 | 11·60 | | Phosphorus | P | 31·0 | 1·83 | | Platinum | Pt | 197·4 | 21·53 | | Potassium (Kalium) | K | 39·0 | 0·865 | | Rhodium | Rh | 104·3 | 12·1 | | Rubidium | Ru | 104·4 | 11·4 | | Selenium | Se | 79·5 | 4·78 | | Silicon | Si | 28·0 | 2·49 | | Silver (Argentum) | Ag | 108·0 | 10·5 | | Sodium (Natrium) | Na | 23·0 | 0·972 | | Strontium | Sr | 87·6 | 2·54 | | Sulphur | S | 32·0 | 2·05 | | Tantalium | Ta | 182·0 | 10·78 | | Tellurium | Te | 129·0 | 6·02 | | Thallium | Tl | 204·0 | 11·91 | | Thorium | Th | 115·7 | 7·8 | | Tin (Stannum) | Sn | 118·0 | 7·28 | | Titanium | Ti | 50·0 | 4·3 | | Tungsten (Wolfram) | W | 184·0 | 7·5 | | Uranium | U | 120·0 | 18·4 | | Vanadium | V | 51·3 | 5·50 | | Yttrium | Y | 61·7 | -- | | Zinc | Zn | 65·0 | 7·14 | | Zirconium | Zr | 89·5 | 4·15 | +----------------------+---------+--------+-----------+

The figures indicating the proportions by weight in which the elements unite with one another are called the combining or atomic weights, because they represent the relative weights of the atoms of the different elements. Since hydrogen is the lightest element, it is taken as the standard, and its combining or atomic weight = 1.

_To find the proportional parts by weight of the elements of any substance whose chemical formula is known_:

RULE.--Multiply together the equivalent and the exponent of each element of the compound; the product will be the proportion by weight of that element in the substance.

_Example_:--Find the proportional weights of the elements of Alcohol C₂H₆O.

Carbon C₂ = equivalent 12 × exponent 2 = 24 Hydrogen H₆ = ” 1 × ” 6 = 6 Oxygen O = ” 16 × ” 1 = 16

Of every 46 lb. of Alcohol, 6 lb. will be H; 16, O; 24, C.

To find the proportions by _volume_, divide by the specific gravity.

COMMON NAMES OF CHEMICAL SUBSTANCES.

_Common Names._ _Chemical Names._

Aqua fortis Nitric acid. Aqua regia Nitro-hydrochloric acid.

Blue vitriol Sulphate of copper.

Cream of tartar Bi-tartrate of potassium. Calomel Chloride of mercury. Chalk Carbonate of calcium. Caustic potash Hydrate of potassium Chloroform Chloride of formyl. Common salt Chloride of sodium. Copperas, or green vitriol Sulphate of iron. Corrosive sublimate Bi-chloride of mercury.

Dry alum Sulphate of aluminium and potassium.

Epsom salts Sulphate of magnesium. Ethiops mineral Black sulphide of mercury.

Galena Sulphide of lead. Glauber’s salt Sulphate of sodium. Glucose Grape sugar.

Iron pyrites Bi-sulphide of iron.

Jeweller’s putty Oxide of tin.

King’s yellow Sulphide of arsenic.

Laughing gas Protoxide of nitrogen. Lime Oxide of calcium. Lunar caustic Nitrate of silver.

Mosaic gold Bi-sulphide of tin. Muriate of lime Chloride of calcium.

Nitre, or saltpetre Nitrate of potash.

Oil of vitriol Sulphuric acid.

Potash Oxide of potassium.

Realgar Sulphide of arsenic. Red lead Oxide of lead. Rust of iron Oxide of iron.

Sal ammoniac Chloride of ammonia. Salt of tartar Carbonate of potassium. Slacked lime Hydrate of calcium. Soda Oxide of sodium. Spirits of hartshorn Ammonia. Spirits of salt Hydrochloric acid. Stucco, or plaster of Paris Sulphate of lime. Sugar of lead Acetate of lead.

Verdigris Basic acetate of copper. Vermilion Sulphide of mercury. Vinegar Acetic acid (diluted). Volatile alkali Ammonia.

Water Oxide of hydrogen. White precipitate Ammoniated mercury. White vitriol Sulphate of zinc.

THERMOMETER.

The following are the formulæ for the conversion of degrees of one scale to those of another:--

(Centigrade° × 9 /5)+ 32 = Fahr.° |(Fahr.° - 32 × 4) / 9 = Réaumur°. | (Réaumur° × 9)/4 + 32 = Fahr.° |(Centigrade° × 4) / 5 = Réaumur°. | (Fahr.° 32 × 5)/9 = Cent.° |(Réaumur° × 5) / 4 = Centigrade°.

FREEZING, FUSING, AND BOILING POINTS.

+------------------------------+---------+------------+-------------+ | | | | | | Substances. | Réaumur.| Centigrade.| Fahrenheit. | | | | | | +------------------------------+---------+------------+-------------+ | | | | | |Bromine freezes at | -17·6° =| -22° =| -7·6° | |Oil, Anise ” | 8 =| 10 =| 50 | |Oil, Olive ” | 8 =| 10 =| 50 | |Oil, Rose ” | 12 =| 15 =| 60 | |Quicksilver ” | -31·5 =| -39·4 =| -39° | |Water ” | 0 =| 0 =| 32° | |Bismuth metal fuses at | 211 =| 264 =| 507° | |Copper ” | 963 =| 1204 =| 2200 | |Gold ” | 963 =| 1204 =| 2200 | |Iodine ” | 95·6 =| 107° =| 224·6° | |Iron ” | 1230 =| 1538 =| 2800 | |Lead ” | 26 =| 325 =| 617 | |Potassium ” | 50 =| 62·5° =| 144·5° | |Silver ” | 530 =| 537·70 =| 1000 | |Sodium ” | 76·5°=| 95·6 =| 204° | |Steel melts at a lower | | | | | temperature than malleable | | | | | iron | -- | -- | -- | |Sulphur fuses at | 54 =| 120 =| 248° | |Tin ” | 189·6°=| 237 =| 459° | |Zinc ” | 329·6°=| 412 =| 773° | |Alcohol boils at | 59·5°=| 74·4 =| 173·1 | |Bromine ” | 46·4 =| 58 =| 136 | |Ether ” | 28·4 =| 35·5 =| 96 | |Iodine ” | 140 =| 175 =| 347 | |Quicksilver ” | 288 =| 360 =| 680 | |Water ” | 80 =| 100 =| 212 | +------------------------------+---------+------------+-------------+

HEAT VALUES OF FUELS.

Pounds of water evaporated by 1 lb. of fuel as follows:--

Straw 1·9 | Coke or Charcoal 6·4 Wood 3·1 | Coal 7·9 Peat 3·8 | Petroleum 14·6

SIGNS AND SYMBOLS USED IN EXPRESSING FORMULAS.

= Sign of equality, denoting that quantities so connected are equal to one another; thus, 3 feet = 1 yard.

+ Sign of addition, signifying _plus_ or more; thus, 4 + 3 = 7.

-Sign of subtraction, signifying _minus_ or less; thus, 4-3 = 1.

× Sign of multiplication, signifying multiplied by or into; thus, 4 × 3 = 12.

÷ Sign of division, signifying divided by; thus, 4 ÷ 2 = 2.

{} () [] Brackets, denoting that the quantities between them are to be treated as one quantity; thus, 5 {3(4 + 2)-6(3-2)} = 5 (18-6) = 60.

Letters are used to shorten or simplify a formula. Supposing we wish to express length × breadth × depth, we may put the initial letters only, thus, _l_ × _b_ × _d_, or, as is usual when algebraical symbols are employed, leave out the sign × between the factors, and write the formula _lbd_.

When division is to be expressed in simple form, the divisor is written under the dividend; thus (_x_ + _y_) ÷ _z_ = (_x_ + _y_) ________ _z_

° ’ ” are signs used to express certain angles in degrees, minutes, and seconds; thus 25 degrees 4 minutes 21 seconds would be expressed 25° 4’ 21”.

√ This sign is called the radical sign, and placed before a quantity indicates that some root of it is to be taken, and a small figure placed over the sign, called the exponent of the root, shows what root is to be extracted.

Thus ²√ _a_ or √ _a_ means the square root of _a_ ∛ _a_ ” cube ” ∜ _a_ ” fourth ”

ρ This sign is used to denote the force of gravity at any given latitude.

π The Greek letter pi is invariably used to denote 3·14159, that is, the ratio borne by the diameter of a circle to its circumference.

When the figure 2 is affixed to any number, as diameter² or 12², the number is to be squared, as 12 × 12 = 144, the square; and with ³ affixed, the number is to be cubed--_i.e._, multiplied twice by itself, as 6³ = 6 × 6 × 6 = 316, the cube of 6.

=ENGLISH WEIGHTS AND MEASURES.=

MEASURES OF LENGTH.

12 lines = 1 inch. | 8 furlongs } 12 inches = 1 foot. | 1760 yards } = 1 statute mile. 3 feet = 1 yard. | 5280 feet } 6 feet = 1 fathom. | 6086 feet = 1 naut. mile. 16½ feet = 1 pole. | 7·92 inches = 1 link. 220 yards = 1 furlong. | 100 links } 66 feet } = 1 chain. 22 yards }

SQUARE MEASURE.

144 sq. inches = 1 sq.foot. | 10 sq. chains = 1 acre. 9 sq. feet = 1 sq.yard. | 1 hectare = 2·471 acres. 30¼ sq.yards}= 1 sq.rod |640 acres = 1 sq. mile. 272¼ feet } or pole. | 30 sq. acres = 1 yard of land. 40 rods = 1 sq.rood. |Sq. ins. × 0·007 = {square foot 4 roods } | { nearly. 160 rods } |Sq. yds. × 0·00021= acres nearly. 4840 yards }= 1 acre. |113·0977 sq. ins. = 1 circular foot. 43560 feet } |183·46 circular ins.= 1 square foot.

SOLID OR CUBIC MEASURE.

1728 cubic inches = 1 cubic foot. | 27 cubic feet = 1 cubic yard. | 128 cub. ft. = {1 cord 40 cub. ft. of rough, or { | of timber {of wood. 50 cub. ft. of hwn. tmbr.= {1 ton or load.|

AVOIRDUPOIS WEIGHT.

16 drachms = 1 ounce. | 20 cwt = 1 ton. 16 ounces = 1 lb. | lbs. × 0·009 = cwt. nearly. 14 lb. = 1 stone. | lbs. × 0·00045 = tons. 28 lb. = 1 qr. cwt. | 7000 grains = 1 lb. avdp. 112 lb. = 1 cwt. | 437½ grains = 1 oz.

TROY WEIGHT.

24 grains = 1 dwt. | 5760 grains = 1 lb. troy. 20 dwt. = 1 ounce. | 480 grains = 1 oz. ” 12 oz. = 1 lb. |

APOTHECARIES’ FLUID MEASURE.

Gallon (C) = 8 pints (O); 1 pint = 20 fluid ounces (oz. weight of water).

Ounce (f ℥) = 8 drachms (f ʒ) = 480 minims (♏) = 720 drops (gtt.).

One wine glass = 4 tablespoonfuls = 16 tablespoonfuls = 2 ounces.

_Symbols._--f. or fl. fluid; s.s. one half; a.a. for each. Thus f℥ss. ½ a fluid ounce.

Apothecaries’ weight, formerly used for dispensing medicines, superseded in 1864. 20 grains = 1 scruple; 3 scruples = 1 drachm; 8 drachms = 1 ounce; 12 ounces = 1 lb. (troy).

LIQUID MEASURE. Cubic in. nearly. 4 gills = 1 pint = 34¾ 2 pints = 1 quart = 69⅓ 4 quarts = 1 gallon = 277·123

FRENCH WEIGHTS AND MEASURES.

WEIGHTS.

Gramme 15·432349 grams troy. Décagramme (= 10 grammes) 5·6438 drachms av. Hectogramme(= 100 grammes) 3·527 oz. av. Kilogramme (= 1000 grammes) 2·204621 lbs. av., or 2·679227 lbs. troy. Quintal (= 100 kilogrammes) 220·462 lbs. av. Tonne (= 1000 kilogrammes) 2204·621 lbs. av. Decigramme (= 1/10th of a gramme) 1·5432 grain. Centigramme(= 1/100th of a gramme) 0·15432 grain. Milligramme(= 1/1000th of a gramme ) 0·015432 grain.

LINEAL MEASURE.

Mètre 3·2808992 feet. Décamètre (= 10 mètres) 32·808992 feet. Hectomètre(= 100 mètres) 328·08992 feet. Kilomètre (= 1000 mètres) 1093·633 yards. Myriamètre(= 10,000 mètres) 6·2138 miles. Decimètre (= 1/10th of a mètre) 3·937079 inches. Centimètre(= 1/100th of a mètre) 0·39371 inch. Millimètre(= 1/1000th of a mètre) 0·03937 inch.

SUPERFICIAL MEASURE

Centiare (= 1 square mètre) 1·196033 square yard. Are(= 100 square mètres) 0·098845 rood. Hectare (= 10,000 square mètres) 2·471143 acres.

MEASURES OF CAPACITY.

Litre (= 1 décimétre cube) 1·760773 pint(61·027 cubic inches). Décalitre (= 10 litres) 2·2009668 gallons. Hectolitre (= 100 litres) 22·009668 ” Kilolitre (= 1000 litres) 220·09668 ” Décilitre (= 1/10th of a litre) ·17607 pint. Centilitre (= 1/100th of a litre) ·017607 pint.

SOLID MEASURE.

Stère (= 1 cubic mètre) 1·31 cubic yard. Décastère (= 10 stères) 13 cubic yards, 2 feet, 21 inches. Décistère (= 1/10th of a stère) 3 cubic feet, 918·7 cubic inches.

FRESH AND SALT WATER COMPARED.

FRESH. SALT. 1 cubic foot at 40° weighs 62·425 lbs. 64 lbs. 1 cubic inch at 40° weighs ·036,126 lbs. ·037,037 lbs. 1 cubic foot at 40° equals 6·242 gallons 6·2 gallons. 1 ton equals 35·943 cubic ft. 35 cubic ft. 1 ton contains at 62° 224 gallons 217 gallons.

VELOCITY OF FALLING FLUIDS.

Falling fluids are governed by the same laws as falling bodies.

Fluid falls 1 foot in a ¼ of a second, 4 feet in ½ of a second, 9 feet in ¾ of a second, and so on.

The velocity of a fluid, flowing through an aperture in the side of a reservoir, is the same that a heavy body would acquire by falling from a height equal to that between the surface of the fluid and the middle of the opening.

The velocity of a fluid flowing out of an aperture is as the square root of the height of the head of the fluid. The theoretical velocity, therefore, in feet per second is as the square root of the product of the space fallen through in feet and 64·333; consequently, for 1 foot it is [Sqrt]64·333 = 8·02 feet. The mean velocity is about 5·4 feet, or 0·673.

PRESSURE OF WATER AT DIFFERENT HEADS.

H. = head in feet. P. = pressure in lbs. per sq. foot. p. = pressure in lbs. per sq. inch.

+------+--------+-------+------+--------+----------+ | H. | P. | p. | H. | P. | p. | +------+--------+-------+------+--------+----------+ | 1 | 62·4 | ·4333 | 9 | 561·6 | 3·9 | | 1·25 | 78 | ·5416 | 10 | 624 | 4·3333 | | 1·5 | 93·6 | ·65 | 20 | 1248 | 8·6666 | | 1·75 | 109·2 | ·7538 | 30 | 1872 | 13 | | 2 | 124·8 | ·8666 | 40 | 2496 | 17·3333 | | 3 | 187·2 |1·3 | 50 | 3120 | 21·6666 | | 4 | 249·6 |1·7333 | 60 | 3744 | 26 | | 5 | 312 |2·1666 | 70 | 4368 | 30·3333 | | 6 | 374·4 |2·6 | 80 | 4992 | 34·6666 | | 7 | 436·8 |3·0333 | 90 | 5616 | 39 | | 8 | 499·2 |3·4666 | | | | +------+--------+-------+------+--------+----------+

TO FIND THE CONTENTS OF A TANK.

To find the number of gallons contained in a tank, multiply the length, width, and depth together, in feet. This gives the contents in cubic feet; multiply by 6·24, and the result is the number of gallons contained. If the dimensions are in inches, use ·003607 in place of 6·24.

SIZES AND WEIGHT OF CORRUGATED GALVANISED IRON SHEETS.

+-----------+----------------+--------------+-------------+ | Thickness | | Weight | | | B.W.G. | Size of Sheets | Per Square | Square Foot | | | | Foot. | per Ton. | +-----------+----------------+--------------+-------------+ | | Feet. | lb. oz. | | | 16 | 6 × 2 to 8 × 3 | 2 1 | 800 | | 17 × 18 | 6 × 2 ” 8 × 3 | 2 4 | 1050 | | 19 × 20 | 6 × 2 ” 8 × 3 | 1 12 | 1300 | | 21 × 22 | 6 × 2 ” 7 × 2½| 1 7 | 1600 | | 23 × 24 | 6 × 2 ” 7 × 2½| 1 3 | 1900 | | 25 × 26 | 6 × 2 ” 7 × 2½| 1 0 | 2250 | +-----------+----------------+--------------+-------------+

THICKNESS AND WEIGHT OF GALVANISED SHEET IRON.

Size of sheet, 2 feet in width by from 6 to 9 feet in length.

+------------+--------------+-------------+---------------+ | Wire | Weight | Wire | Weight | | Gauge. | Per Square | Gauge. | Per Square | | | Foot. | | Foot. | +------------+--------------+-------------+---------------+ | No. | Oz. | No. | Oz. | | 30 | 10 | 22 | 21 | | 29 | 11 | 21 | 24 | | 28 | 12 | 20 | 28 | | 27 | 14 | 19 | 33 | | 26 | 15 | 18 | 37 | | 25 | 16 | 17 | 43 | | 24 | 17 | 16 | 48 | | 23 | 19 | 14 | 60 | +------------+--------------+-------------+---------------+

QUALITIES OF DIFFERENT ROPES EXPRESSED RELATIVELY.

+--------------+----------+-------------+--------+-------------+ | | Strength.| Rigidity. | Weight | | | | | | Dry. | Stretching. | +--------------+----------+-------------+--------+-------------+ | Italian Hemp | -- | 1 | 1 | } | | Baltic ” | 0·7 ·9 | 0·8 to 0·9 | 1 | }1/7 to 1/12| | Manilla ” | 0·9 to 1 | 0·75 | 0·88 | } | | Flax | 0·9 | low | -- | 1/75 | | Iron Wire | 3 | high | 4 | -- | | Steel | 6 | high | 4 | -- | +--------------+----------+-------------+--------+-------------+

Steel wire rope stretches about 1/360, 1/250, and 1/100, of 1/4, 1/3, and 1/2 the breaking weight.

THE ATMOSPHERE.

The composition of the atmosphere is by volume, oxygen 20·8, nitrogen 79·2; by weight, oxygen 23, nitrogen 77. There are also minute quantities of carbon dioxide, aqueous vapour, and ammonia.

The barometer falls about ½” for each 500’ increase of altitude the mean temperature being 50° Fahr.

WEIGHT OR PRESSURE.

= 14·706 lbs. per square inch. = 29·92 inches of mercury. = 33·7 feet of water.

SQUARES, CUBES, SQUARE ROOTS, AND CUBE ROOTS.

+---------+--------+-----------+-------------+---------+ | | | | Square | Cube | | No. | Square | Cube | Root | Root | | | | | √ | ∛ | +---------+--------+-----------+-------------+---------+ | 1 | 1 | 1 | 1·0 | 1·0 | | 2 | 4 | 8 | 1·414 | 1·259 | | 3 | 9 | 27 | 1·732 | 1·442 | | 4 | 16 | 64 | 2·0 | 1·587 | | 5 | 25 | 125 | 2·236 | 1·709 | | 6 | 36 | 216 | 2·449 | 1·817 | | 7 | 49 | 343 | 2·645 | 1·912 | | 8 | 64 | 512 | 2·828 | 2·0 | | 9 | 81 | 729 | 3·0 | 2·080 | | 10 | 100 | 1000 | 3·162 | 2·154 | | 11 | 121 | 1331 | 3·316 | 2·223 | | 12 | 144 | 1728 | 3·464 | 2·289 | | 13 | 169 | 2197 | 3·60 | 2·35 | | 14 | 196 | 2744 | 3·74 | 2·41 | | 15 | 225 | 3375 | 3·87 | 2·46 | | 16 | 256 | 4096 | 4·0 | 2·51 | | 17 | 289 | 4913 | 4·12 | 2·58 | | 18 | 324 | 5832 | 4·24 | 2·62 | | 19 | 361 | 6859 | 4·35 | 2·66 | | 20 | 400 | 8000 | 4·47 | 2·71 | | 25 | 625 | 15625 | 5·0 | 2·92 | | 30 | 900 | 27000 | 5·47 | 3·10 | | 35 | 1225 | 42875 | 5·91 | 3·27 | | 40 | 1600 | 64000 | 6·32 | 3·41 | | 45 | 2025 | 91125 | 6·70 | 3·55 | | 50 | 2500 | 125000 | 7·07 | 3·68 | | 55 | 3025 | 166375 | 7·41 | 3·80 | | 60 | 3600 | 216000 | 7·24 | 3·91 | | 65 | 4225 | 274625 | 8·06 | 4·02 | | 70 | 4900 | 343000 | 8·36 | 4·12 | | 75 | 5625 | 421875 | 8·66 | 4·41 | | 80 | 6400 | 512000 | 8·94 | 4·30 | | 85 | 7225 | 614125 | 9·21 | 4·39 | | 90 | 8100 | 729000 | 9·48 | 4·48 | | 95 | 9025 | 857375 | 9·74 | 4·56 | | 100 | 10000 | 1000000 | 10·00 | 4·64 | | 110 | 12100 | 1331000 | 10·48 | 4·79 | | 120 | 14400 | 1728000 | 10·95 | 4·93 | | 130 | 16900 | 2197000 | 11·40 | 5·06 | | 140 | 19600 | 2744000 | 11·83 | 5·19 | | 150 | 22500 | 3375000 | 12·24 | 5·31 | | 160 | 25600 | 4096000 | 12·64 | 5·42 | | 170 | 28900 | 4913000 | 13·03 | 5·53 | | 180 | 32400 | 5832000 | 13·41 | 5·64 | | 190 | 36100 | 6859000 | 13·78 | 5·74 | | 200 | 40000 | 8000000 | 14·14 | 5·84 | | 210 | 44100 | 9261000 | 14·49 | 5·94 | | 220 | 48400 | 10648000 | 14·83 | 6·03 | | 230 | 52900 | 12167000 | 15·16 | 6·12 | | 240 | 57600 | 13824000 | 15·49 | 6·21 | | 250 | 62500 | 15625000 | 15·81 | 6·29 | | 260 | 67600 | 17576000 | 16·12 | 6·38 | | 270 | 72900 | 19683000 | 16·43 | 6·46 | | 280 | 78400 | 21952000 | 16·73 | 6·54 | | 290 | 84100 | 24389000 | 17·02 | 6·61 | | 300 | 90000 | 27000000 | 17·32 | 6·69 | | 310 | 96100 | 29791000 | 17·60 | 6·76 | | 320 | 102400 | 32768000 | 17·88 | 6·83 | | 330 | 108900 | 35937000 | 18·16 | 6·91 | | 340 | 115600 | 39304000 | 18·43 | 6·97 | | 350 | 122500 | 42875000 | 18·17 | 7·04 | | 360 | 129600 | 46656000 | 18·97 | 7·11 | | 370 | 136900 | 50653000 | 19·23 | 7·17 | | 380 | 144400 | 54872000 | 19·49 | 7·24 | | 390 | 152100 | 59319000 | 19·74 | 7·30 | | 400 | 160000 | 64000000 | 20·00 | 7·36 | | 410 | 168100 | 68921000 | 20·24 | 7·42 | | 420 | 176400 | 74088000 | 20·49 | 7·48 | | 430 | 184900 | 79507000 | 20·73 | 7·54 | | 440 | 193600 | 85184000 | 20·97 | 7·60 | | 450 | 202500 | 91125000 | 21·21 | 7·66 | | 460 | 211600 | 97336000 | 21·44 | 7·71 | | 470 | 220900 | 103823000 | 21·67 | 7·77 | | 480 | 230400 | 110592000 | 21·90 | 7·82 | | 490 | 240100 | 117649000 | 22·13 | 7·88 | | 500 | 250000 | 125000000 | 22·36 | 7·93 | | 510 | 260100 | 132651000 | 22·58 | 7·98 | | 520 | 270400 | 140608000 | 22·80 | 8·04 | | 530 | 280900 | 148877000 | 23·02 | 8·09 | | 540 | 291600 | 157464000 | 23·23 | 8·14 | | 550 | 302500 | 166375000 | 23·45 | 8·19 | | 560 | 313600 | 175616000 | 23·66 | 8·24 | | 570 | 324900 | 185193000 | 23·87 | 8·29 | | 580 | 336400 | 195192000 | 24·08 | 8·33 | | 590 | 348100 | 205379000 | 24·29 | 8·38 | | 600 | 360000 | 216000000 | 24·49 | 8·43 | | 610 | 372100 | 226981000 | 24·69 | 8·48 | | 620 | 384400 | 238328000 | 24·90 | 8·52 | +---------+--------+-----------+-------------+---------+

TABLE TO CALCULATE WAGES AND OTHER PAYMENTS.

+----------+-------------------+------------------+--------------+ | Year. | Per Month. | Per Week. | Per Day. | +----------+-------------------+------------------+--------------+ | £ | £ s. d. | £ s. d. | s. d. | | 1 | 0 1 8 | 0 0 4½ | 0 0¾ | | 2 | 0 3 4 | 0 0 9¼ | 0 1¼ | | 3 | 0 5 0 | 0 1 1¾ | 0 2 | | 4 | 0 6 8 | 0 1 6½ | 0 2¾ | | 5 | 0 8 4 | 0 1 11 | 0 3¼ | | 6 | 0 10 0 | 0 2 1¾ | 0 4 | | 7 | 0 11 8 | 0 2 8¼ | 0 4½ | | 8 | 0 13 4 | 0 3 1 | 0 5¼ | | 9 | 0 15 0 | 0 3 5½ | 0 6 | | 10 | 0 16 8 | 0 3 10¼ | 0 6½ | | 11 | 0 18 4 | 0 4 3¾ | 0 7¼ | | 12 | 1 0 0 | 0 4 7½ | 0 8 | | 13 | 1 1 8 | 0 5 0 | 0 8½ | | 14 | 1 3 4 | 0 5 4½ | 0 9¼ | | 15 | 1 5 0 | 0 5 9¼ | 0 9¾ | | 16 | 1 6 8 | 0 6 1¾ | 0 10½ | | 17 | 1 8 4 | 0 6 6½ | 0 11¼ | | 18 | 1 10 0 | 0 6 11 | 0 11¾ | | 19 | 1 11 8 | 0 7 3½ | 1 0½ | | 20 | 1 13 4 | 0 7 8¼ | 1 1¼ | | 30 | 2 10 0 | 0 11 6½ | 1 7¾ | | 40 | 3 6 8 | 0 15 4½ | 2 2¼ | | 50 | 4 3 4 | 0 19 2¾ | 2 9 | | 60 | 5 0 0 | 1 3 1 | 3 3½ | | 70 | 5 16 8 | 1 6 11 | 3 10 | | 80 | 6 13 4 | 1 10 9¼ | 4 4½ | | 90 | 7 10 0 | 1 14 7½ | 4 11½ | | 100 | 8 6 8 | 1 18 5½ | 5 5¾ | +----------+-------------------+------------------+--------------+

If the Wages be Guineas instead of Pounds, for each Guinea add 1_d._ to each month, or 1/4_d._ to each week.

HANDY UNIVERSAL INTEREST TABLE.

(By Alfred Fryer.)

Showing the Interest, to the 100th part of a farthing, on any Sum from £1 to £1,000,000, for any number of days, at any rate per cent.

+----------+---------+-----+------+-----+--------+ | | £ | s. | d. | f. | 100ths | +----------+---------+-----+------+-----+--------+ | 1 | 0 | 0 | 1 | 2 | 3 | | 2 | 0 | 0 | 1 | 1 | 26 | | 3 | 0 | 0 | 1 | 3 | 89 | | 4 | 0 | 0 | 2 | 2 | 52 | | 5 | 0 | 0 | 3 | 1 | 15 | | 6 | 0 | 0 | 3 | 3 | 78 | | 7 | 0 | 0 | 4 | 2 | 41 | | 8 | 0 | 0 | 5 | 1 | 4 | | 9 | 0 | 0 | 5 | 3 | 67 | | 10 | 0 | 0 | 6 | 2 | 30 | | 20 | 0 | 1 | 1 | 0 | 60 | | 30 | 0 | 1 | 7 | 2 | 90 | | 40 | 0 | 2 | 2 | 1 | 21 | | 50 | 0 | 2 | 8 | 3 | 51 | | 60 | 0 | 3 | 3 | 1 | 81 | | 70 | 0 | 3 | 10 | 0 | 11 | | 80 | 0 | 4 | 4 | 2 | 41 | | 90 | 0 | 4 | 11 | 0 | 71 | | 100 | 0 | 5 | 5 | 3 | 1 | | 200 | 0 | 10 | 11 | 2 | 3 | | 300 | 0 | 16 | 5 | 1 | 4 | | 400 | 1 | 1 | 11 | 0 | 5 | | 500 | 1 | 7 | 4 | 3 | 7 | | 600 | 1 | 12 | 10 | 2 | 8 | | 700 | 1 | 18 | 4 | 1 | 10 | | 800 | 2 | 3 | 10 | 0 | 11 | | 900 | 2 | 9 | 3 | 3 | 12 | | 1,000 | 2 | 14 | 9 | 2 | 14 | | 2,000 | 5 | 9 | 7 | 0 | 27 | | 3,000 | 8 | 4 | 4 | 2 | 41 | | 4,000 | 10 | 19 | 2 | 0 | 55 | | 5,000 | 13 | 13 | 11 | 2 | 68 | | 6,000 | 16 | 8 | 9 | 0 | 82 | | 7,000 | 19 | 3 | 6 | 2 | 96 | | 8,000 | 21 | 18 | 4 | 1 | 10 | | 9,000 | 24 | 13 | 1 | 3 | 23 | | 10,000 | 27 | 7 | 11 | 1 | 37 | | 20,000 | 54 | 15 | 10 | 2 | 74 | | 30,000 | 82 | 3 | 10 | 0 | 11 | | 40,000 | 109 | 11 | 9 | 1 | 48 | | 50,000 | 136 | 19 | 8 | 2 | 85 | | 60,000 | 164 | 7 | 8 | 0 | 22 | | 70,000 | 191 | 15 | 7 | 1 | 59 | | 80,000 | 219 | 3 | 6 | 0 | 96 | | 90,000 | 246 | 11 | 6 | 0 | 32 | | 100,000 | 273 | 19 | 5 | 1 | 70 | | 200,000 | 547 | 18 | 10 | 3 | 40 | | 300,000 | 821 | 18 | 4 | 1 | 9 | | 400,000 | 1095 | 17 | 9 | 2 | 79 | | 500,000 | 1369 | 17 | 3 | 0 | 49 | | 600,000 | 643 | 16 | 8 | 2 | 19 | | 700,000 | 917 | 16 | 1 | 3 | 89 | | 800,000 | 2191 | 15 | 7 | 1 | 59 | | 900,000 | 2465 | 15 | 0 | 3 | 29 | |1,000,000 | 2739 | 14 | 6 | 0 | 99 | +----------+---------+-----+------+-----+--------+

THE RULE.--Multiply the number of £ upon which the interest is to be calculated by the number of days, and then multiply this product by the rate of interest, strike out the last two figures to the right hand, and find from the table the interest on the remaining figures.

_Example._--What is the interest of £271 for 90 days at 7 per cent. per ann.?

Multiply £271 by 90 number of days ------ then multiply 24390 by 7 rate of interest ------ 170730 strike out last 2 figures, viz.: 30, and in the table £ | s. | d. | f. | 100ths. | against 1000 you find 2 | 14 | 9 | 2 | 14 | ” 700 ” 1 | 18 | 4 | 1 | 10 | ” 7 ” 0 | 0 | 4 | 2 | 41 | ------------------------------- 4 | 13 | 6 | 1 | 65 |

If the product of the number of £ on which the interest be calculated × number of days × rate of interest is, after elision of the last two figures, a multiple of a million, multiply the figures in table against 1,000,000 by the number of that multiple.

AUSTRALIAN MINING REGULATIONS.

NEW SOUTH WALES.

By the Mining Act of 1874, the Governor was empowered to proclaim Crown lands to be gold-fields, and to grant “miners’ rights” at a fee of 10_s._, between January and June exclusive, of each year, and 5_s._ after that date in each year, subject to certain regulations to be from to time to time prescribed. All miners’ rights terminate with the last day of the year, and without a miner’s right no person is allowed to mine for gold, under a penalty not exceeding £10. Business licences may also be granted enabling persons to occupy Crown lands within gold-fields for business purposes, on payment of a fee of £1 for a year, and 10_s._ for six months. Leases of auriferous lands may be obtained in accordance with the regulations for the time being, the rent to be fixed by the Governor in Council (£1 per acre for one to twenty-five acres alluvial and quartz reef). Special leases may be granted up to 100 acres. By the regulations issued on March 31, 1882, it is enacted that any parcel of new or unworked land, taken possession of with a view of obtaining a lease, shall be efficiently and continuously worked from the date of possession by not less than two men to four acres or less, and an additional man to every other two acres, under pain of forfeiture of the title to the land. The holder of a miner’s right may apply for authority to search for gold, and the holder of a mineral licence may apply for authority to search for minerals on land aforesaid.

At the expiration of two months the Warden may grant an authority to search on such land, and the holder may, within the period named in the authority, remove from any vein or lode outcropping at the surface 28 lb. weight, but must not break the ground.

Application to lease may be made and lodged with the Warden of the district, or nearest Warden’s Clerk, within one month from date of authority to search:

1. By the holder of an authority to search, the area not to exceed 20 acres for gold-mining, or 80 acres for other minerals.

2. By the holder of a miner’s right, the area not to exceed 20 acres of ordinary auriferous land, or 40 acres of alluvial auriferous land, where the mining operations will be conducted through basaltic rock formation, or where steam machinery is necessary to contend against water, or where a large outlay of money is necessary.

3. By the holder of a mineral licence to mine for silver, lead, tin, antimony, the area not to exceed 80 acres.

4. By the holder of a prospecting licence, within 30 days after discovery of an auriferous quartz vein in a prospecting area, area not to exceed 20 acres.

5. By the holder of a miner’s right or mineral licence, for the purpose of cutting races, conveying water or detritus to any mine, tramway, machine site, smelting works, water conservation, or other purpose connected with mining.

With every application to lease, the applicant, not being the owner of the land, shall deposit for rent for first half year, 10_s._ for every acre or part of an acre. Fees are required for the survey of the leasehold and road thereto, and also for appraising damage.

The owner may agree with the applicant to lease upon the amount of compensation and the mode of payment of same, otherwise an appraiser appointed by the Government may assess the amount of compensation to be paid by the applicant to the owner. If the applicant fail to pay the compensation awarded within the time specified, the application shall become void, and all moneys deposited shall become forfeited.

VICTORIA.

Miners’ rights are issued at the rate of 5_s._ per annum, and consolidated miners’ rights may be issued on the application of the manager or trustees of any company agreeing to work in partnership any claims registered under the Act, on payment of a sum at the prescribed rate multiplied by the number of miners’ rights so consolidated. Miners’ rights entitle the holders to take possession of, and reside on and mine, so much of the Crown lands as may be prescribed by the bylaws of the Local Mining Board. Business licences enable the holders to occupy and carry on business on the gold-fields, on lands not exceeding one acre in extent, and are issued at £2 10_s._ for six months, and £5 for twelve months. A lease may be granted of not more than 100 acres in one lot for such term as the Governor may determine and at a nominal rent, to any holder of a miners’ right who may be desirous to prospect for gold in any place where sinking through basalt will be necessary, and to which no part of any gold workings shall be nearer than five miles, one mile being allowed to be marked off for the prospecting, and the lease of 100 acres to be granted only in case of remunerative gold being found.

Gold-mining leases may be granted under Part I. of the “Mines Act 1890,” of Crown lands, pastoral areas, also lands alienated in fee since December 29, 1884, lands licensed or leased (with right of purchase) since December 29, 1884.

Leases to mine for gold and silver may be granted under Part II. of the “Mines Act 1890,” of lands alienated in fee prior to December 29, 1884.

The rent on gold-mining leases of any lands--except lands alienated in fee prior to December 29, 1884--is at the rate of 5_s._ per acre per annum, payable half-yearly in advance; and for lands alienated in fee prior to December 29, 1884, the rent is, for any area up to 40 acres, £1 per annum, payable quarterly in advance in each case. On mineral leases the rent is not less than 3_d._ or more than £5 per acre per annum, payable half-yearly, in advance.

The amount to be lodged with an application for mining lease is £5, and such further sum as may be required to cover cost of survey.

Licences to cut, construct, and use races, drains, dams, and reservoirs for mining purposes, may be granted for a term not to exceed fifteen years, at a minimum rent of £2 per annum in advance.

SOUTH AUSTRALIA.

A miner’s right authorises the holder to prospect for any metal, mineral, coal, or oil, the property of the Crown; under a gold claim of 20 acres, a mineral claim not exceeding 40 acres, and a coal or oil claim, 640 acres. Ownership of claim confers the right to reside thereon, and preferential right to a lease.

The dimensions of a gold claim are for an ordinary reef claim, 100 by 600 feet, and an ordinary alluvial claim 30 by 30 feet, with a labour condition requiring one man to be kept employed. A mineral claim of 40 acres requires two men; coal and oil claims (640 acres) require eight men. A business licence (quarter acre in township, and one acre on other land) costs 10_s._ for six months and £1 for one year. Occupation licence (half acre), 2_s._ per annum, term fourteen years. A person may hold any number of claims (except alluvial claims, of which only one can be held at one time), but for each claim must hold a miner’s right.

Gold leases not exceeding 20 acres, term forty-two years, rent 1_s._ per acre and 6_d._ in the pound on net profits; labour, one man to every 5 acres. Mineral leases not exceeding 40 acres, term forty-two years, rent 1_s._ per acre, and 6_d._ in the pound on net profits; labour, one man to every 10 acres. Coal and oil leases (640 acres), term forty-two years, rent 6_d._ per acre until coal or oil is found in payable quantities, then 1_s._ per acre; labour, one man for every 40 acres. Miscellaneous lease for salt and gypsum, 40 acres; mineral springs, 20 acres, and smelting works’ site, 5 acres, term forty-two years; labour for salt and gypsum and mineral springs, two men for each 40 acres.

Any number of leases may be held, but a miner’s right for each is required. All claims must be constantly worked, and must be registered within thirty days after being pegged out.

WESTERN AUSTRALIA.

On April 17, 1884, amended Mining Regulations were issued, empowering the Governor to proclaim any portion of Crown land to be a gold-field, and to appoint Wardens, who could grant miner’s rights to any person upon payment of £1 per year, authorising the holder to search and mine for gold on any waste land upon registering the occupation of the claim with the Warden or other duly appointed officer.

Alluvial ordinary claims to comprise an area of 16 by 16 yards for one person, ordinary river and steam claims to have a frontage of 20 yards on the course of the river or stream, and a depth of 50 yards on both banks; ordinary quartz claims not to exceed 50 feet in length on the supposed course of the reef by a width not exceeding 400 feet. Any ground taken up for mining and unoccupied and unworked for ten days to be considered as abandoned.

On October 1, 1886, “Regulations for the Management of Gold-fields” came into operation, dealing with the conditions under which a miner desirous of prospecting may mark off and hold a protection area; also as regards alluvial claims, and the rewards to be had for discoveries of new gold-fields.

By an additional amended regulation, granted under regulations of February 2, 1888, any protection area which after the date of the grant thereof comes within the limits of a proclaimed gold-field, may, notwithstanding such proclamation, continue to be held until the expiration of twelve months from the date of such grant, or until payable gold on such area is discovered, which ever shall first happen. The labour conditions must however be fully complied with, or the extension of time will cease, and the protection area will be forfeited.

Gold-mining leases are granted for areas not exceeding 25 acres, at an annual rent, payable in advance, of 20_s._ per acre. The term may not exceed twenty-one years. The leases are liable to cancellation unless worked by the proper number of men, or machinery power equal to the men. The leases can be determined by giving three months’ notice, and the lessees have power to remove all machinery used on the land.

QUEENSLAND.

On payment of 10_s._ the Governor may cause to be issued to any person (not being an Asiatic or African alien), a mining licence for one year, and on payment of the sum of £4 a business licence. All applications for mineral leases to be made on the prescribed form, and to be accompanied by the proper survey fee and the first year’s rent. The yearly rental of every lease to be at the rate of 10_s._ per acre, payable in advance, the term not to exceed twenty-one years, but a further lease of twenty-one years may be granted on such terms as the Minister deems equitable. Area not to exceed 100 acres.

Mining without a right is punishable by removal of the offender from the field, and the infliction of a fine of £10, or one month’s imprisonment.

Miners desirous of prospecting for gold may mark off and hold protection areas, ranging according to the distance from a proclaimed gold-field of 150 to 400 yards square. Such areas have to be pegged, registered, and continuously worked. On payable gold being found and reported to the Warden, the prospectors are entitled to a reward claim which varies from two to twenty claims of the ordinary area. 50 feet frontage are allowed to each miner on river and creek claims. On ordinary quartz claims, 50 feet along the line of reef, by a width of 400 feet, are allowed. The extent of ground in any lode claim not to exceed 3 chains by 5 chains, alluvial claim not to exceed 4 chains by 4 chains. This area may be increased by the Warden when the ground is poor, or expensive machinery has been erected. Europeans holding miners’ rights, which are granted for ten years or less on payment of an annual rate of 10_s._, are allowed to occupy and enclose, for the purpose of residence, an area of land not exceeding a quarter of an acre, to be marked off in a rectangular block, or as near thereto as possible, the frontage of which to any road, creek, or water shall not exceed 72 feet, the boundaries to be defined by corner pegs 3 inches in diameter and standing 18 inches out of the ground, and can also occupy, under certain conditions, market-garden areas not exceeding 5 acres. They are also entitled to mine in Crown lands, to make dams, races, and tramways, to divert waters, to put up and remove any building, and to use any timber, gravel, or clay for their own building purposes. Upon erecting buildings or making improvements on a business or residence area, to the value of £5, the holder can have such area registered as exempt from the condition of residence for a period not exceeding one year.

Leases of land not exceeding 25 acres for any term not exceeding 21 years are also granted for mining purposes at a yearly rental of £1 per acre. These leases, however, are not granted on new gold-fields until two years after proclamation.

The Mineral Lands Act of 1892, applies to lands on gold-fields and gives the power to the holders of miner’s rights and licences to mine on land sold, subject to reservation of gold and silver, on obtaining the written sanction of the Warden or commissioner.

TASMANIA.

A miner’s right, or prospector’s protection order, issued under the Gold-fields Act (the fee for a miner’s right being 5_s._, and a prospector’s licence 10_s._ per annum), authorises the holder to reside upon a gold-field, and to occupy a quarter of an acre for residence, and entitles him to a claim for mining purposes:--Alluvial, single claim, 35 yards by 35 yards; united claims, up to 10 men, 110 yards by 110 yards. Creek claims; 35 yards by 35 yards along course of creek; united claims not to exceed six men’s area. Extended alluvial claims; 70 yards by 70 yards, up to 170 yards by 170 yards for six men; also to take any quantity of water and of timber required for mining purposes. Extended alluvial claims of one acre for ground previously worked and abandoned may be taken up. Prospecting claims, gold, not exceeding 10 acres. Fee for registration, which is not compulsory, 2_s._ 6_d._; survey 25_s._ United claim of 10, fee 5_s._; survey, £2. Leases not to exceed 10 acres, except in special cases by permission of the Minister; term, ten years; rent, £1 per acre. Leases may be amalgamated to the extent of 60 acres. Lessee has the right to renewal for ten years, rent not to exceed £3 an acre. Fee for preparation of lease, £1; transfer, 10_s._ Survey fee, 10 acres, £3 15_s._ ordinary land; £5 10_s._ heavy bush. On the West Coast the survey fees are: 1 acre and under, £1 15_s._; 2 acres, and under 5 acres, £3 15_s._; under 10 acres, £5 10_s._, up to a maximum of £23 for not exceeding 320 acres.

Leases are liable to forfeiture by the Governor in Council if the rent is not paid in advance, or the labour conditions are not complied with.

Licences to occupy land upon a gold-field, for the purpose of cultivation, are issued under the Waste Lands Acts. Area, 5 acres or under, rent £2.

NEW ZEALAND.

The price of a “miner’s right” is 10_s._ per year, which authorises the holder to mine on Crown lands throughout the colony outside of a native district; and 20_s._, which authorises him to mine on native lands and Crown lands, or such other sum as shall not be less than the sum which the Governor may have agreed to pay to the owners of the land as consideration for the right to mine thereon. Consolidated miners’ rights are issued at the rate of a single miner’s right (10_s._), multiplied by the number of miners’ rights which the consolidated right is to represent. Business licences, to be in force for twelve or six months, are issued on payment in advance of £3 for a yearly, and £1 10_s._ for a half-yearly licence respectively. The holder of a miner’s right is entitled to enter upon any Crown land for the purpose of prospecting and searching for gold, and to take and maintain possession of a parcel or parcels of land and work the same, subject to the regulations and provisions of the Act; he is also authorised to cut timber for removal or for the erection of a place of residence or of business, and with the Warden’s consent, to make tramways or roads for mining purposes. Claims are of four kinds--alluvial deposits and river or creek beds; quartz lodes, reefs, and leaders; sea-beach claims; prospecting claims and areas. Claims may be marked out by any person desiring the exclusive occupation of the land, but they must be continuously worked, or they are liable to forfeiture.

The holder of a miner’s right can obtain a licence for the occupation of land as a licensed holding by paying the necessary expenses for surveying, &c., together with a deposit of £5 in respect of such application.

INDEX

A

Adobie hut, 127, 128

Aërial tramways, 112

Amalgam, Retort for small quantities of, 142; squeezing, 155

Amalgamation of gold, 30

Amalgamators, 91-93

Aneroid barometer, Use of, for leveling, 160, 161

Antifriction compound, 165

Aqueous origin of ore deposits, 36-38

Assay apparatus, Simple form of, 14, 15

Assaying gold by amalgamation, 30

Areas, To lay out, 174, 175

Atherton, on native sulphide of gold, 45, 46

Atmosphere, 190

Atomic weights, 181, 182

Australian mining regulations, 194, _et seq._; New South Wales, 194; Victoria, 195; S. Australia, 195; W. Australia, 195; Queensland, 198; Tasmania, 200

B

Battery, the best way to test value of lodes, 31

Becker, on Comstock lode, 42, 43

Belting, Data as to, 178, 180

Bischof, experiment on formation of dendroidal gold, 39

Black jack, 33

Blanket tables, 79

Boilers, How to clean, 164

Boiling points, 184

Boring, 172

Bottom, Signs of, 20

Braidwood nugget, 54

Brass, How to clean, 165

Brückner furnace, 105

Bucket, Hide, 139

Bulk of materials, 180

Burra Burra Mine, 24

Bush bed, 130

Bynoe harbour, Tin at, 32

C

California pump, 171

Challenger ore feeder, 74, 75

Charcoal, To make, 141

Chemical formulas, 182

Chlorine as a lixiviator, 73-75

Company formation, 113-126

Comstock lode, 42, 43

Copper mine at Burra Burra, 24

Copper plates, Scaling, 144, 145; Silvering, 149; Dressing, 151

Correspondence, How to make copies of, 137

Cube roots, 191

Cubes, 191

Cyanide of potassium, Use of, in extracting gold, 95, 96

D

Daintree, on deposition of gold from chloride, 51

Diamond drilling, 173

Directors of companies, 114 _et seq._

Dodge stone-breakers, 69, 70

Dolly, 152

Drift, Origin of gold in, 49

Dry blowing, 18

Dugout, 128

Duncan pan, 91

E

Electricity as a motive power and transmitter, 111, 112

Electrolytic process of extracting gold, 96-99

Elements, Table of, 181, 182

Eurieowie, Tin at, 32

F

Filter, 135, 136

Fire, Mode of producing, 137

Fire-lute, 166

Flooded Stream, How to cross a, 138

Flumes, 63

Forge, Temporary, 140

Freezing-points, 184

Frue vanner, 89, 90

Fuels, Heat values of, 184

Furnaces used in calcining, 101 _et seq._

Fusing points, 184

G

Gold, Value of, 1; Early notices of, 1, 2; Origin and sources of, 2-7; Modes of occurrence, 10, 11; Prospecting for, 13 _et seq._; Signs of, 26; Assaying, by amalgamation, 30; associated with tin ores, 32, 33; Relation of, to volcanic action, 36; its probable mode of occurrence in early geological times, 38, 39; Mode of deposition in quartz, 39, 55, 57; Formation of sulphides of, 39, 40; Precipitation of, in pyrites, 41, 42, 51-54; Solution of, by mine water, 42; Opinion as to growth of, in drift deposits 48; Daintree on its deposition from chloride, 51; Wilkinson on its precipitation on iron pyrites, 51, 52

Gold (Alluvial) Origin of, 17, 49, 50, 51; Prospecting for, 17

Gold extraction, 11, 12, 59 _et seq._; necessity of scientific procedure, 60; German organisation, 60; early methods, 61; modern methods, 61 _et seq._; hydraulicing, 62, 65; mills and crushers, 66-72; power and water for batteries, 73, 74; ore feeders, 74, 75; stamp mills, 76-78; screens, 78; blanket tables, 79; treatment of pyritous ores, 80; mode of saving the gold, 81; treatment of ferruginous ores, 82; cleaning and scaling plates, 83; retorting amalgam, 84-86; percussion tables, 88; Frue vanner, 89, 90; pan concentrators, 90; amalgamators, 91-93; lixiviation, 93 _et seq._; calcination, 100 _et seq._; how to avoid loss in cleaning up, 148

Gold-field, Mount Brown 17, 18

Griffin Mill, 67, 69

Grusonwerk ball mill, 71

Gutters, 20

H

Hammock, 130, 132

Heated bearings, Cooling compound for, 163

Heat values of fuels, 184

Horse-power of engines, 144, amount required for pumping water, 172

Horse-shoe furnace, 103

Howell-White furnace, 104, 105

Huntingdon mill, 69

Hydraulicing, 62, 65

Hydraulics, 171

Hydro-thermal origin of early deposits, 37, 38

I

Interest Tables, 193

Iron, prevention of rust on, 165

Iron extractor, 148

Iron sheets, size and weight of, 189

Ironstone “blows” as indicators of lodes, 26

J

Johnson, experiments on deposition of gold, 55-57

L

Lamp, Slush, 139

Leads, Course of, 19

Le Conte, on ore deposits, 36, 37

Lemichel syphon, 66, 67

Lenticular lodes, 24, 25

Levelling instruments, 160, 161

Living places, 127-130

Lobley, on gold, 36

Lodes, nature of, 8-10; prospecting for, 22; grass as an indicator of, 22; not of igneous origin, 23; Quartz fragments as indicators of, 23; Usual trend of, in Australia, 23; Sinuous outcrops of, 25, 26; Determining the value of, 26, 28, 31; Underlie of, in Australia, 27; Explanation of shutes in, 43; why junctions of, are richest in metallic ores, 44; proofs of their being formed now, 44; Newbery, on gold in pyritous lodes, 47; Double faulting of, 72

Lode tin, 32

Long tom, 62

Loss in blasting, How to prevent, 142

M

Machinery, Protection of, from rusting, 166

Mear’s process, 94

Measuring inaccessible distances, 157; the width of a river, 157, 158; height of a tree, 159, 160; height of objects, 161

Medicine case, 136

Mensuration, 175

Mercury, Retort for small quantities of, 143; Mode of supplying, to mortar boxes, 145

Mercury extractor, 155

Metals, 33

Mine managers, 115 _et seq._

Mine surveying problems, 176

Mining regulations, 194-201

Misfires, How to deal with, 141

Molesworth furnace, 106

Monitor, 64

Mount Bischoff tin mine, 24

Mount Brown gold-field, 17, 18

Mount Morgan gold mine, 23, 94, 95

Mount Shoobridge, Tin at, 32

N

Names of common chemical substances, 183

Newbery, Experiments by, on modern growth of lodes, 44, 45, 53; on gold in pyritous lodes, 47; experiments in depositing gold on sulphides, 52, 53

Newbery and Vautin process, 94

New machines and processes, Advice as to adoption of, 120-122

New Zealand, Mining regulations of, 201

Northern territory hammock, 130-132

Nuggets, Position of, 17; Formation of, 17; Origin of, 50, 53-58

O

Ore Deposits, Le Conte’s conclusions as to, 36, 37

Ore reserves, Calculation of, 168-170

Ore values, Estimating, 170

Organic matter as a precipitant of gold, 51, 52, 53

Otto engines, 110, 111

P

Percussion tables, 88

Pipes, How to clear, 164

Plants as a source of water, 134, 135

Plattner process, 94

Plummer blocks, Cleaning greasy, 163

Pollok process, 95

Power for mills, 147

Prospect, First, 29; Determining value of, 29, 30, 31

Puddlers, 153-155

Pump, 155, 171

Purchase of mines, Advice as to, 123

Pyrites as a precipitant of gold, 41, 42, 51-54; Modern deposition of, 45; Mode of occurrence of gold in, 46, 47

Pyritous ore, Mode of treatment of, 80

Q

Quartz veins, Rosales’s igneous theory of, 34; objections thereto, 35, 36

R

Rainfall, 178

Reef. See _Lodes_

Retort for small quantities of amalgam, 142; and of mercury, 143

Reverberatory furnaces, 101 _et seq._

Right angle, 158

Rivers, To measure width of, 157, 158

Robbery in gold-mills, Mode of preventing, 124-126

Ropes, Durability of, 173; Qualities of, 190

Rope-splicing, 166

Rosales on origin of quartz veins, 32-34

Rotomahana district, White and Pink Terraces in, 36

Rust, Solvent for, 165; Protecting iron and steel from, 165

Rutile, 32, 33

S

School of Mines, S. Australian, 118

Screens, 78, 79

Shaft, Size of, 19, 27; Logging up, 27, 28; Depth of, 162; Connection of, with underground workings, 176; Data connected with, 177

Sheet-iron, Thickness and weight of, 189, 190

Shutes, Explanation of, 43

Signs, 185

Silica terraces in the Rotomahana district, 36

Silver ores, 31, 32

Silvering copper plates, 149

Skey, experiments on formation of sulphides, 39, 40; and on their properties, 41

Sluice plates, 156

Smelting, Rough, 141

Soap, Serviceable, 138

Specific gravity, 181, 182

Square roots, 191

Squares, 191

Stamp mills, 76, 78; Power for, 147

Steel, How to prevent rust in, 165

Stetefeldt shaft furnace, 106

Stream tin, 32

Sulphide of gold, Formation of, 39, 40, 45, 46

Sulphides, Experiments on properties of, 41, 42, 53; calcination of, 100 _et seq._

T

Tank, to find contents of, 189

Telegraphic code, 138

Tent, 128-130

Thames gold-field, Siliceous sinter in, 36

Thermometer scales, Table of, 184

Thwaite-Denny furnace, 105, 106

Thwaite power gas system, 110

Thwaites’ furnace, 102

Timber, Data as to, 174

Tin, Minerals mistaken for, 32; How to distinguish them from, 33

Tin-mines at Mount Bischoff, 24

Tin ores, 32

Tree, To measure height of, 160

Tulloch ore feeder, 74, 75

V

Vein, to find lost part of, 167

Velocity of falling fluids, 188

W

Wages, Table for calculating, 192

Washing table, 79

Water, Purifying, 132, 133; Roots as a source of, 134, 135; Filtering of, 135; Mode of supplying, to stamper boxes, 146; Plan for raising, 163; Data regarding, 171; Fresh and Salt, compared, 188; Pressure of, 189

Water bag, 136

Waterless power, 109-112

Watson & Denny pan, 90

Weight of materials, 180

Weights and measures, 186, 187

Welcome nugget, 54, 55

Welcome Stranger nugget, 54

Wilkinson, on deposition of gold in iron pyrites, 51, 52

Windlass, 153

Wolfram, 32, 33

Woodside nuggets, 57

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A Handbook for Engineers and Officers in the Royal Navy and Mercantile Marine, Including the Management of the Main and Auxiliary Engines on Board Ship.

By JOHN G. LIVERSIDGE, A.M.I.C.E., Commander Engineer, Malta.

_Contents._--General Description of Marine Machinery.--The Conditions of Service and Duties of Engineers of the Royal Navy. --Entry and Conditions of Service of Engineers of the Leading S.S. Companies.--Raising Steam.--Duties of a Steaming Watch on Engines and Boilers.--Shutting off Steam.--Harbour Duties and Watches.--Adjustments and Repairs of Engineslic Machinery. --Air-Compressing Pumps.--Refrigerating Machines.--Machinery of Destroyers.--Th.--Preservation and Repairs of “Tank” Boilers.--The Hull and its Fittings.--Cleaning and Painting Machinery.-- Reciprocating Pumps, Feed Heaters, and Automation Feed-Water Regulators.--Evaporators.--Steam Boats.--Electric Light Machinery. --Hydraulic Machinery.--Air Compressing Pumps.--Refrigerating Machines.--The Machinery of Destroyers--The Management of Water-Tubs Boilers.--Regulations for Entry of Assistant Engineers, R.N.-- Questions given in Examinations for Promotion of Engineers, R.N.-- Regulations respecting Board of Trade Examinations for Engineers, &c

“The contents CANNOT FAIL TO BE APPRECIATED.”--_The Steamship._

“This VERY USEFUL BOOK.... Illustrations are of GREAT IMPORTANCE in a work of this kind, and it is satisfactory to find that SPECIAL ATTENTION has been given in this respect.”--_Engineers’ Gazette._

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In Large Crown 8vo, Cloth. Fully Illustrated. 5s. net.

OIL FUEL: ITS SUPPLY, COMPOSITION, AND APPLICATION.

BY SIDNEY H. NORTH, LATE EDITOR OF THE “PETROLEUM REVIEW.”

Contents.--The Sources of Supply.--Economic Aspect of Liquid Fuel.-- Chemical Composition of Fuel Oils.--Conditions of Combustion in Oil Fuel Furnaces.--Early Methods and Experiments.--Modern Burners and Methods.--Oil Fuel for Marine Purposes.--For Naval Purposes.--On Locomotives.--For Metallurgical and other Purposes.--Appendices. --Index.

“Everyone interested in this important question will welcome Mr. North’s excellent text-book.”--_Nature._

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LONDON: CHARLES GRIFFIN & CO., LIMITED, EXETER STREET, STRAND.

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Second Edition, Revised. With numerous Plates reduced from Working Drawings and 280 Illustrations in the Text. 21s.

A MANUAL OF LOCOMOTIVE ENGINEERING:

A Practical Text-Book for the Use of Engine Builders, Designers and Draughtsmen, Railway Engineers, and Students.

By WILLIAM FRANK PETTIGREW, M.Inst.C.E.

With a Section on American and Continental Engines.

By ALBERT F. RAVENSHEAR, B.Sc., Of His Majesty’s Patent Office.

_Contents._--Historical Introduction, 1763-1863.--Modern Locomotives: Simple.--Modern Locomotives: Compound.--Primary Consideration in Locomotive Design.--Cylinders, Steam Chests, and Stuffing Boxes.--Pistons, Piston Rods, Crossheads, and Slide Bars. --Connecting and Coupling Rods.--Wheels and Axles, Axle Boxes, Hornblocks, and Bearing Springs.--Balancing.--Valve Gear.--Slide Valves and Valve Gear Details.--Framing, Bogies and Axle Tracks, Radial Axle Boxes.--Boilers.--Smokebox, Blast Pipe, Firebox Fittings.--Boiler Mountings.--Tenders.--Railway Brakes.-- Lubrication.--Consumption of Fuel, Evaporation and Engine Efficiency.--American Locomotives.--Continental Locomotives.-- Repairs, Running, Inspection, and Renewals.--Three Appendices.-- Index.

“The work CONTAINS ALL THAT CAN BE LEARNT from a book upon such a subject. It will at once rank as THE STANDARD WORK UPON THIS IMPORTANT SUBJECT.”--_Railway Magazine._

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AT PRESS. In Large 8vo. Fully Illustrated.

=LOCOMOTIVE COMPOUNDING AND SUPERHEATING.=

By J. F. GAIRNS.

CONTENTS.--Introductory.--Compounding and Superheating for Locomotives.--A Classification of Compound Systems for --The History and Development of the Compound Locomotives. Locomotive.--Two-Cylinder Non-Automatic Systems.--Two-Cylinder Automatic Systems.--Other Two-Cylinder Systems.--Three-Cylinder Systems.--Four-Cylinder Tandem Systems.--Four-Cylinder Two-Crank Systems (other than Tandem).--Four-Cylinder Balanced Systems.--Four-Cylinder Divided and Balanced Systems.--Articulated Compound Engines.--Triple-Expansion Locomotives.--Compound Rack Locomotives.--Concluding Remarks Concerning Compound Locomotives. --The Use of Superheated Steam for Locomotives.--Index.

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_In Large 8vo. Handsome Cloth. With Plates and Illustrations. 16s._

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LIGHT RAILWAYS AT HOME AND ABROAD.

By WILLIAM HENRY COLE, M.Inst.C.E.,

Late Deputy-Manager, North-Western Railway, India.

_Contents._--Discussion of the Term “Light Railways.”--English Railways, Rates, and Farmers.--Light Railways in Belgium, France, Italy, other European Countries, America and the Colonies, India, Ireland.--Road Transport as an alternative.--The Light Railways Act, 1896.--The Question of Gauge.--Construction and Working.-- Locomotives and Rolling-Stock.--Light Railways in England, Scotland, and Wales.--Appendices and Index.

“Will remain, for some time yet a Standard Work in everything relating to Light Railways.”--_Engineer._

“The whole subject is EXHAUSTIVELY and PRACTICALLY considered. The work can be cordially recommended as INDISPENSABLE to those whose duty it is to become acquainted with one of the prime necessities of the immediate future.”--_Railway Official Gazette._

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LONDON: CHARLES GRIFFIN & CO., LIMITED, EXETER STREET, STRAND.

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Fourth Edition, Thoroughly Revised and Greatly Enlarged. _With Numerous Illustrations. Price 10s. 6d_.

VALVES AND VALVE-GEARING: A PRACTICAL TEXT-BOOK FOR THE USE OF ENGINEERS, DRAUGHTSMEN, AND STUDENTS.

By CHARLES HURST, Practical Draughtsman.