Chapter 4

But the Perche district does not rest on the Solitaire, for there has been abundance of mineral wealth discovered throughout its extent. Four miles south of this prospect, on the middle fork of the Perche, is an actual mine--the Bullion--which was purchased by four or five Western mining men for $10,000, and yielded $11,000 in twenty days. The ore contains horn and native silver. On the same fork are the Iron King and Andy Johnson, both recently discovered and promising properties, and there is a valuable mine now in litigation on the south fork of the Perche, with scores of prospects over the entire district. Now that one or two sensational strikes have attracted attention, and capital is developing paying mines, the future of the Perche District seems assured.

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THE SOY BEAN.

The _British Medical Journal_ says that Prof. E. Kinch, writing in the _Agricultural Students' Gazette_, says that the Soy bean approaches more nearly to animal food than any other known vegetable production, being singularly rich in fat and in albuminoids. It is largely used as an article of food in China and Japan. Efforts have been made to acclimatize it in various parts of the continent of Europe, and fair success has been achieved in Italy and France; many foods are made from it and its straw is a useful fodder.

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ON A NEW ARC ELECTRIC LAMP.

[Footnote: Paper read at the British Association, Southampton. Revised by the Author.--_Nature_.]

By W.H. PREECE.

Electric lamps on the arc principle are almost as numerous as the trees in the forest, and it is somewhat fresh to come upon something that is novel. In these lamps the carbons are consumed as the current flows, and it is the variation in their consumption which occasions the flickering and irregularity of the light that is so irritating to the eyes. Special mechanical contrivances or regulators have to be used to compensate for this destruction of the carbons, as in the Siemens and Brush type, or else refractory materials have to be combined with the carbons, as in the Jablochkoff candle and in the lamp Soleil. The steadiness of the light depends upon the regularity with which the carbons are moved toward each other as they are consumed, so as to maintain the electric resistance between them a constant quantity. Each lamp must have a certain elasticity of regulation of its own, to prevent irregularities from the variable material of carbon used, and from variations in the current itself and in the machinery.

In all electric lamps, except the Brockie, the regulator is in the lamp itself. In the Brockie system the regulation is automatic, and is made at certain rapid intervals by the motor engine. This causes a periodic blinking that is detrimental to this lamp for internal illumination.

M. Abdank, the inventor of the system which I have the pleasure of bringing before the Section, separates his regulator from his lamp. The regulator may be fixed anywhere, within easy inspection and manipulation, and away from any disturbing influence in the lamp. The lamp can be fixed in any inaccessible place.

_The Lamp_ (Figs. 1, 2, and 3.)--The bottom or negative carbon is fixed, but the top or positive carbon is movable, in a vertical line. It is screwed at the point, C, to a brass rod, T (Fig. 2), which moves freely inside the tubular iron core of an electromagnet, K. This rod is clutched and lifted by the soft iron armature, A B, when a current passes through the coil, M M. The mass of the iron in the armature is distributed so that the greater portion is at one end, B, much nearer the pole than the other end. Hence this portion is attracted first, the armature assumes an inclined position, maintained by a brass button, t, which prevents any adhesion between the armature and the core of the electromagnet. The electric connection between the carbon and the coil of the electromagnet is maintained by the flexible wire, S.

The electromagnet, A (Fig. 1), is fixed to a long and heavy rack, C, which falls by its own weight and by the weight of the electromagnet and the carbon fixed to it. The length of the rack is equal to the length of the two carbons. The fall of the rack is controlled by a friction break, B (Fig. 3), which acts upon the last of a train of three wheels put in motion by the above weight. The break, B, is fixed at one end of a lever, B A, the other end carrying a soft iron armature, F, easily adjusted by three screws. This armature is attracted by the electromagnet, E E (whose resistance is 1,200 ohms), whenever a current circulates through it. The length of the play is regulated by the screw, V. The spring, L, applies tension to the break.

_The Regulator_.--This consists of a balance and a cut-off.

_The Balance_ (Figs. 4 and 5) is made with two solenoids. S and S', whose relative resistances is adjustable. S conveys the main current, and is wound with thick wire having practically no resistance, and S' is traversed by a shunt current, and is wound with fine wire having a resistance of 600 ohms. In the axes of these two coils a small and light iron tube (2 mm. diameter and 60 mm. length) freely moves in a vertical line between two guides. When magnetized it has one pole in the middle and the other at each end. The upward motion is controlled by the spring, N T. The spring rests upon the screw, H, with which it makes contact by platinum electrodes. This contact is broken whenever the little iron rod strikes the spring, N T.

The positive lead from the dynamo is attached to the terminal, B, then passes through the coil, S, to the terminal, B', whence it proceeds to the lamp. The negative lead is attached to terminal, A, passing directly to the other terminal, A', and thence to the lamp.

The shunt which passes through the fine coil, S', commences at the point, P. The other end is fixed to the screw, H, whence it has two paths, the one offering no resistance through the spring, T N, to the upper negative terminal, A'; the other through the terminal, J, to the electromagnet of the break, M, and thence to the negative terminal of the lamp, L'.

_The Cut-off_.--The last part of the apparatus (Fig. 4) to be described is the cut-off, which is used when there are several lamps in series. It is brought into play by the switch, C D, which can be placed at E or D. When it is at E, the negative terminal, A, is in communication with the positive terminal, B, through the resistance, R, which equals the resistance of the lamp, which is, therefore, out of circuit. When it is at D the cut-off acts automatically to do the same thing when required. This is done by a solenoid, V, which has two coils, the one of thick wire offering no resistance, and the other of 2,000 ohms resistance. The fine wire connects the terminals, A' and B. The solenoid has a movable soft iron core suspended by the spring, U. It has a cross-piece of iron which can dip into two mercury cups, G and K, when the core is sucked into the solenoid. When this is the case, which happens when any accident occurs to the lamp, the terminal, A, is placed in connection with the terminal, B, through the thick wire of V and the resistance, R, in the same way as it was done by the switch, C D.

_Electrical Arrangement_.--The mode in which several lamps are connected up in series is shown by Fig. 6. M is the dynamo machine. The + lead is connected to B1 of the balance it then passes to the lamp, L, returning to the balance, and then proceeds to each other lamp, returning finally to the negative pole of the machine. When the current enters the balance it passes through the coil, S, magnetizing the iron core and drawing it downward (Fig. 4). It then passes to the lamp, L L', through the carbons, then returns to the balance, and proceeds back to the negative terminal of the machine. A small portion of the current is shunted off at the point, P, passing through the coil, S', through the contact spring, T N, to the terminal, A', and drawing the iron core in opposition to S. The carbons are in contact, but in passing through the lamp the current magnetizes the electromagnet, M (Fig. 2), which attracts the armature, A B, that bites and lifts up the rod, T, with the upper carbon, a definite and fixed distance that is easily regulated by the screws, Y Y. The arc then is formed, and will continue to burn steadily as long as the current remains constant. But the moment the current falls, due to the increased resistance of the arc, a greater proportion passes through the shunt, S' (Fig. 4), increasing its magnetic moment on the iron core, while that of S is diminishing. The result is that a moment arrives when equilibrium is destroyed, the iron rod strikes smartly and sharply upon the spring, N T. Contact between T and H is broken, and the current passes through the electromagnet of the break in the lamp. The break is released for an instant, the carbons approach each other. But the same rupture of contact introduces in the shunt a new resistance of considerable magnitude (viz., 1,200 ohms), that of the electromagnets of the break. Then the strength of the shunt current diminishes considerably, and the solenoid, S, recovers briskly its drawing power upon the rod, and contact is restored. The carbons approach during these periods only about 0.01 to 0.02 millimeter. If this is not sufficient to restore equilibrium it is repeated continually, until equilibrium is obtained. The result is that the carbon is continually falling by a motion invisible to the eye, but sufficient to provide for the consumption of the carbons.

The contact between N T and H is never completely broken, the sparks are very feeble, and the contacts do not oxidize. The resistances inserted are so considerable that heating cannot occur, while the portion of the current abstracted for the control is so small that it may be neglected.

The balance acts precisely like the key of a Morse machine, and the break precisely like the sounder-receiver so well known in telegraphy. It emits the same kind of sounds, and acts automatically like a skilled and faithful telegraphist.

This regulation, by very small and short successive steps, offers several advantages: (1) it is imperceptible to the eye; (2) it does not affect the main current; (3) any sudden instantaneous variation of the main current does not allow a too near approach of the carbon points. Let, now, an accident occur; for instance, a carbon is broken. At once the automatic cut-off acts, the current passes through the resistance, R, instead of passing through the lamp. The current through the fine coil is suddenly increased, the rod is drawn in, contact is made at G and K, and the current is sent through the coil, R. As soon as contact is again made by the carbons, the current in the coil, S, is increased, that of the thick wire in V diminished, and the antagonistic spring, U, breaks the contact at G and K. The rupture of the light is almost invisible, because the relighting is so brisk and sharp.

I have seen this lamp in action, and its constant steadiness leaves nothing to be desired.

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APPARATUS FOR OBTAINING PURE WATER FOR PHOTOGRAPHIC USE.

Our readers are well aware that water as found naturally is never absolutely free from dissolved impurities; and in ordinary cases it contains solid impurities derived both from the inorganic and organic kingdoms, together with gaseous substances; these latter being generally derived from the atmosphere.

By far the purest water which occurs in nature is rain-water, and if this be collected in a secluded district, and after the air has been well washed by previous rain, its purity is remarkable; the extraneous matter consisting of little else than a trace of carbonic acid and other gases dissolved from the air. In fact, such water is far purer than any distilled water to be obtained in commerce. The case is very different when the rain-water is collected in a town or densely populated district, more especially if the water has been allowed to flow over dirty roofs. The black and foully-smelling liquid popularly known as soft water is so rich in carbonaceous and organic constituents as to be of very limited use to the photographer; but by taking the precaution of fitting up a simple automatic shunt for diverting the stream until the roofs have been thoroughly washed, it becomes possible to insure a good supply of clean and serviceable soft water, even in London. Several forms of shunt have been devised, some of these being so complex as to offer every prospect of speedy disorganization; but a simple and efficient apparatus is figured in _Engineering_ by a correspondent who signs himself "Millwright," and as we have thoroughly proved the value of an apparatus which is practically identical, we reproduce the substance of his communication.

A gentleman of Newcastle, a retired banker, having tried various filters to purify the rain-water collected on the roof of his house, at length had the idea to allow no water to run into the cistern until the roof had been well washed. After first putting up a hard-worked valve, the arrangement as sketched below has been hit upon. Now Newcastle is a very smoky place, and yet my friend gets water as pure as gin, and almost absolutely free from any smack of soot.

The sketch explains itself. The weight, W, and the angle of the lever, L, are such, that when the valve, V, is once opened it goes full open. A small hole in the can C, acts like a cataract, and brings matters to a normal state very soon after the rain ceases.

The proper action of the apparatus can only be insured by a careful adjustment of the weight, W, the angle through which the valve opens, and the magnitude of the vessel, C. It is an advantage to make the vessel, C, somewhat broader in proportion to its height than represented, and to provide it with a movable strainer placed about half way down. This tends to protect the cataract hole, and any accumulation of leaves and dirt can be removed once in six months or so. Clean soft water is valuable to the photographer in very many cases. Iron developer (wet plate) free from chlorides will ordinarily remain effective on the plate much longer than when chlorides are present, and the pyrogallic solution for dry-plate work will keep good for along time if made with soft water, while the lime which is present in hard water causes the pyrogallic acid to oxidize with considerable rapidity. Negatives that have been developed with oxalate developer often become covered with a very unsightly veil of calcium oxalate when rinsed with hard water, and something of a similar character occasionally occurs in the case of silver prints which are transferred directly from the exposure frame to impure water.

To the carbon printer clean rain-water is of considerable value, as he can develop much more rapidly with soft water than with hard water; or, what comes to the same thing, he can dissolve away his superfluous gelatine at a lower temperature than would otherwise be necessary.

The cleanest rain-water which can ordinarily be collected in a town is not sufficiently pure to be used with advantage in the preparation of the nitrate bath, it being advisable to use the purest distilled water for this purpose; and in many cases it is well to carefully distill water for the bath in a glass apparatus of the kind figured below.

A, thin glass flask serving as a retort. The tube, T, is fitted air-tight to the flask by a cork, C.

B, receiver into which the tube, T, fits quite loosely.

D, water vessel intended to keep the spiral of lamp wick, which is shown as surrounding T, in a moist condition. This wick acts as a siphon, and water is gradually drawn over into the lower receptacle, E.

L, spirit lamp, which may, in many cases, be advantageously replaced by a Bunsen burner.

A small metal still, provided with a tin condensing worm, is, however, a more generally serviceable arrangement, and if ordinary precautions are taken to make sure that the worm tube is clean, the resulting distilled water will be nearly as pure as that distilled in glass vessels.

Such a still as that figured below can be heated conveniently over an ordinary kitchen fire, and should find a place among the appliances of every photographer. Distilled water should always be used in the preparation of emulsion, as the impurities of ordinary water may often introduce disturbing conditions.--_Photographic News_.

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BLACK PHOSPHORUS.

By P. THENARD.

The author refers to the customary view that black phosphorus is merely a mixture of the ordinary phosphorus with traces of a metallic phosphide, and contends that this explanation is not in all cases admissible. A specimen of black or rather dark gray phosphorus, which the author submitted to the Academy, became white if melted and remained white if suddenly cooled, but if allowed to enter into a state of superfusion it became again black on contact with either white or black phosphorus. A portion of the black specimen being dissolved in carbon disulphide there remained undissolved merely a trace of a very pale yellow matter which seemed to be amorphous phosphorus.--_Comptes Rendus_.

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COMPOSITION OF STEEP WATER.

According to M. C. Leeuw, water in which malt has been steeped has the following composition:

Organic matter. 0.56 per cent. Mineral matter. 0.52 " ---- Total dry matter. 1.08 " ---- Nitrogen. 0.033 "

The mineral matter consists of--

Potash. 0.193 " Phosphoric acid. 0.031 " Lime. 0.012 " Soda. 0.047 " Magnesia. 0.016 " Sulphuric acid. 0.007 " Oxide of iron. traces. Chlorine and silica. 0.212 "

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SCHREIBER'S APPARATUS FOR REVIVIFYING BONE-BLACK.

We give opposite illustrations of Schreiber's apparatus for revivifying bone-black or animal charcoal. The object of revivification is to render the black fit to be used again after it has lost its decolorizing properties through service--that is to say, to free its pores from the absorbed salts and insoluble compounds that have formed therein during the operation of sugar refining. There are two methods employed--fermentation and washing. At present the tendency is to abandon the former in order to proceed with as small a stock of black as possible, and to adopt the method of washing with water and acid in a rotary washer.

Figs. 1 and 2 represent a plan and elevation of a bone-black room, containing light filters, A, arranged in a circle around wells, B. These latter have the form of a prism with trapezoidal base, whose small sides end at the same point, d, and the large ones at the filter. The funnel, E, of the washer, F, is placed in the space left by the small ends of the wells, so that the black may be taken from these latter and thrown directly into the washer. The washer is arranged so that the black may flow out near the steam fitter, G, beneath the floor. The discharge of this filter is toward the side of the elevator, H, which takes in the wet black below, and carries it up and pours it into the drier situated at the upper part of the furnace. This elevator, Figs. 3 and 4, is formed of two vertical wooden uprights, A, ten centimeters in thickness, to which are fixed two round-iron bars the same as guides. The lift, properly so-called, consists of an iron frame, C, provided at the four angles with rollers, D, and supporting a swinging bucket, E, which, on its arrival at the upper part of the furnace, allows the black to fall to an inclined plane that leads it to the upper part of the drier. The left is raised and lowered by means of a pitch-chain, F, fixed to the middle of the frame, C, and passing over two pulleys, G, at the upper part of the frame and descending to the mechanism that actuates it. This latter comprises a nut, I, acting directly on the chain; a toothed wheel, K, and a pinion, J, gearing with the latter and keyed upon the shaft of the pulleys, L and M. The diameter of the toothed wheel, K, is 0.295 of a meter, and it makes 53.4 revolutions per minute. The diameter of the pinion is 0.197 of a meter, and it makes 80 revolutions per minute. The pulleys, M and L, are 0.31 of a meter in diameter, and make 80 revolutions per minute. Motion is transmitted to them by other pulleys, N, keyed upon a shaft placed at the lower part, which receives its motion from the engine of the establishment through the intermedium of the pulley, O. The diameter of the latter is 0.385 of a meter, and that of N is 0.58. They each make 43 revolutions per minute.

The elevator is set in motion by the simple maneuver of the gearing lever, P, and when this has been done all the other motions are effected automatically.

_The Animal Black Furnace_.--This consists of a masonry casing of rectangular form, in which are arranged on each side of the same fire-place two rows of cast-iron retorts, D, of undulating form, each composed of three parts, set one within the other. These retorts, which serve for the revivification of the black, are incased in superposed blocks of refractory clay, P, Q, S, designed to regularize the transmission of heat and to prevent burning. These pieces are kept in their respective places by crosspieces, R. The space between the retorts occupied by the fire-place, Y, is covered with a cylindrical dome, O, of refractory tiles, forming a fire-chamber with the inner surface of the blocks, P, Q, and S. The front of the surface consists of a cast-iron plate, containing the doors to the fire-place and ash pan, and a larger one to allow of entrance to the interior to make repairs.

One of the principal disadvantages of furnaces for revivifying animal charcoal has been that they possessed no automatic drier for drying the black on its exit from the washer. It was for the purpose of remedying this that Mr. Schreiber was led to invent the automatic system of drying shown at the upper part of the furnace, and which is formed of two pipes, B, of undulating form, like the retorts, with openings throughout their length for the escape of steam. Between these pipes there is a closed space into which enters the waste heat and products of combustion from the furnace. These latter afterward escape through the chimney at the upper part.

In order that the black may be put in bags on issuing from the furnace, it must be cooled as much as possible. For this purpose there are arranged on each side of the furnace two pieces of cast iron tubes, F, of rectangular section, forming a prolongation of the retorts and making with them an angle of about 45 degrees. The extremities of these tubes terminate in hollow rotary cylinders, G, which permit of regulating the flow of the black into a car, J (Fig. 1), running on rails.

From what precedes, it will be readily understood how a furnace is run on this plan.