Chapter 3

One of the hinderances to the production of a regular and steady light in electric illumination is the absence of perfect uniformity in the carbons. This defect has more than once been pointed out by us, and we are glad to notice any attempt to remedy an admitted evil. To this end we illustrate above a machine for manufacturing carbons, invented by William Cunliffe. The object the inventor has in view is not only the better but the more rapid manufacture of carbons, candles, or electrodes for electric lighting or for the manufacture of rods or blocks of carbon or other compressible substances for other purposes, and his invention consists in automatic machinery whereby a regular and uniform pressure and compression of the carbon is obtained, and the rods or blocks are delivered through the formers, in a state of greater density and better quality then hitherto. The machine consists of two cylinders, A A', placed longitudinally, as shown at Fig. 1, and in reversed position in relation to each other. In each cylinder works a piston or plunger, a, with a connecting rod or rods, b; in the latter case the ends of the rods have right and left handed threads upon which a sleeve, c, with corresponding threads, works. This sleeve, c, is provided with a hand wheel, so that by the turning it the stroke of the plungers, a a, and the size of the chambers, A A', is regulated so that the quantity of material to be passed through the dies or formers is thereby determined and may be indicated. In front of the chambers, A A', are fixed the dies or formers, d d, which may have any number of perforations of the size or shape of the carbon it is intended to mould. The dies are held in position by clamp pieces, e e, secured to the end of the chambers A A', by screws, and on each side of these clamp pieces are guides, with grooves, in which moves a bar with a crosshead, termed the guillotine, and which moves across the openings of the dies, and opening or closing them. Near the front end of the cylinders are placed small pistons or valves, f f, kept down in position by the weighted levers, g g (see Fig. 2, which is drawn to an enlarged scale), which, when the pressure in the chamber exceeds that of the weighted levers connected to the safety valve, f, the latter is raised and the guillotine bar, h, moved across the openings of the dies by the connecting rods, h', thereby allowing the carbon to be forced through the dies. In the backward movement of the piston, a, a fresh supply of material is drawn by atmospheric pressure through the hoppers, B B', alternately. At the end of the stroke the arms of the rocking levers (which are connected by tension rods with the tappet levers) are struck by the disk wheel or regulator, the guillotine is moved back and replaced over the openings of the dies, ready for the next charge, as shown. The plungers are operated by hydraulic, steam, compressed air, or other power, the inlet and outlet of such a pressure being regulated by a valve, an example of which is shown at Fig. 1, and provided with the tappet levers, i i, hinged to the valve chest, C, as shown, and attached to spindles, i' i', operating the slide valves, and struck alternately at the end of each stroke, thus operating the valves and the guillotine connections, i² and i³. The front ends of the cylinders may be placed at an angle for the more convenient delivery of the moulded articles.--_Iron_.

* * * * *

NEW ELECTRIC BATTERY LIGHTS.

There has lately been held, at No. 31 Lombard Street, London, a private exhibition of the Holmes and Burke primary galvanic battery. The chief object of the display was to demonstrate its suitability for the lighting of railway trains, but at the same time means were provided to show it in connection with ordinary domestic illumination, as it is evident that a battery will serve equally as well for the latter as for the former purpose. Already the great Northern express leaving London at 5:30 P.M. is lighted by this means, and satisfactory experiments have been made upon the South-western line, while the inventors give a long list of other companies to which experimental plant is to be supplied. The battery shown, in Lombard Street consisted of fifteen cells arranged in three boxes of five cells each. Each box measured about 18 in. by 12 in. by 10 in., and weighed from 75 lb. to 100 lb. The electromotive force of each cell was 1.8 volts and its internal resistance from 1/40 to 1/50 of an ohm, consequently the battery exhibited had, under the must favorable circumstances, a difference of potential of 27 volts at its poles, and a resistance of 0.3 ohm.

When connected to a group of ten Swan lamps of five candle power, requiring a difference of potential of 20 volts, it raised them to vivid incandescence, considerably above their nominal capacity, but it failed to supply eighteen lamps of the same kind satisfactorily, showing that its working capacity lay somewhere between the two. A more powerful lamp is used in the railway carriages, but as there was only one erected it was impossible to judge of the number that a battery of the size shown would feed. _Engineering_ says the trial, however, demonstrated that great quantities of current were being continuously evolved, and if, as we understood, the production can be maintained constant for about twenty-four hours without attention, the new battery marks a distinct step in this kind of electric lighting. Of the construction of the battery we unfortunately can say but little, as the patents are not yet completed, but we may state that the solid elements are zinc and carbon, and that the novelty lies in the liquid, and in the ingenious arrangement for supplying and withdrawing it.

Ordinarily one charge of liquid will serve for twenty-four hours working, but this, of course, is entirely determined by the space provided for it. It is sold at sevenpence a gallon, and each gallon is sufficient, we are informed, to drive a cell while it generates 800 ampere hours of current, or, taking the electromotive force at 1.8 volts, it represents (800 x 1.8) / 746 = 1.93 horse-power hours. The cost of the zinc is stated to be 35 per cent. of that of the fluid, although it is difficult to see how this can be, for one horse-power requires the consumption of 895.2 grammes of zinc per hour, or 1.96 lb., and this at 18_l_. per ton, would cost 1.93 pence per pound, or 3.8 pence per horse-power hour. This added to 3.6 pence for the fluid, would give a total of 7.4 pence per horse-power per hour, and assuming twenty lamps of ten candle power to be fed per horse-power, the cost would be about one-third of a penny per hour per lamp.

Mr Holmes admits his statement of the consumption of zinc does not agree with what might be theoretically expected but he bases it upon the result of his experiments in the Pullman train, which place the cost at one farthing per hour per light. At the same time he does not profess that the battery can compete in the matter of cost with mechanically generated currents on a large scale, but he offers it as a convenient means of obtaining the electric light in places where a steam engine or a gas engine is inadmissible, as in a private house, and where the cost of driving a dynamo machine is raised abnormally high by reason of a special attendant having to be paid to look after it.

But he has another scheme for the reduction of the cost, to which we have not yet alluded, and of which we can say but little, as the details are not at present available for publication. The battery gives off fumes which can be condensed into a nitrogenous substance, valuable, it is stated, as a manure, while the zinc salts in the spent liquid can be recovered and returned to useful purposes. How far this is practicable it is at present impossible to say, but at any rate the idea represents a step in the right direction, and if the electricians can follow the example of the gas manufacturers and obtain a revenue from the residuals of galvanic batteries, they will greatly improve their commercial position. There is nothing impossible in the idea, and neither is it altogether novel, although the way of carrying it out may be. In 1848, Staite, one of the early enthusiasts in electric lighting, patented a series of batteries from which he proposed to recover sulphate, nitrate, and chloride of zinc, but we never heard that he obtained any success.

* * * * *

NEW ELECTRIC RAILWAY.

The original electric railway laid down by Messrs. Siemens and Halske at Berlin seems likely to be the parent of many others. One of the most recent is the underground electric line laid down by the firm in the mines of Zankerodain Saxony. An account of this railway has appeared in _Glaser's Annalen_, together with drawings of the engine, which we are able to reproduce. They are derived from a paper by Herr Fischer, read on the 19th December, 1882, before the Electro-Technical Union of Germany. The line in question is 700 meters long--770 yards--and has two lines of way. It lies 270 meters--300 yards--below the surface of the ground. It is worked by an electric locomotive, hauling ten wagons at a speed of 12 kilometers, or 7½ miles per hour. The total weight drawn is eight tons. The gauge is a narrow one, so that the locomotive can be made of small dimensions. Its total length between the buffer heads is 2.43 meters; its height 1.04 meters; breadth 0.8 meter; diameter of wheels, 0.34 meter. From the rail head to the center of the buffers is a height of 0.675 meter; and the total weight is only 1550 kilogrammes, or say 3,400 lb. We give a longitudinal section through the locomotive. It will be seen that there is a seat at each end for the driver, so that he can always look forwards, whichever way the engine may be running. The arrangements for connection with the electric current are very simple. The current is generated by a dynamo machine fixed outside the mine, and run by a small rotary steam engine, shown in section and elevation, at a speed of 900 revolutions per minute. The current passes through a cable down the shaft to a T-iron fixed to the side of the heading. On this T-iron slide contact pieces which are connected with the electric engine by leading wires. The driver by turning a handle can move his engine backward or forward at will. The whole arrangement has worked extremely well, and it is stated that the locomotive, if so arranged, could easily do double its present work; in other words, could haul 15 to 16 tons of train load at a speed of seven miles an hour. The arrangements for the dynamo machine on the engine, and its connection with the wheels, are much the same as those used in Sir William Siemens' electric railway now working near the Giant's Causeway.--_The Engineer_.

* * * * *

THE EARLIEST GAS-ENGINE.

Lebon, in the certificate dated 1801, in addition to his first patent, described and illustrated a three-cylinder gas-engine in which an explosive mixture of gas and air was to have been ignited by an electric spark. This is a curious anticipation of the Lenior system, not brought out until more than fifty years later; but there is no evidence that Lebon ever constructed an engine after the design referred to. It is an instructive lesson to would-be patentees, who frequently expect to reap immediate fame and fortune from their property in some crude ideas which they fondly deem to be an "invention," to observe the very wide interval that separates Lebon from Otto. The idea is the same in both cases; but it has required long years of patient work, and many failures, to embody the idea in a suitable form. It is almost surprising, to any one who has not specially studied the matter, to discover the number of devices that have been tried with the object of making an explosion engine, as distinguished from one deriving its motive power from the expansion of gaseous fluids. A narrative of some of these attempts has been presented to the Societe des Ingenieurs Civils; mostly taken in the first place from Stuart's work upon the origin of the steam engine, published in 1820, and now somewhat scarce. It appears from this statement that so long ago as 1794, Robert Street described and patented an engine in winch the piston was to be driven by the explosion of a gaseous mixture whereof the combustible element was furnished by the vaporization of _terebenthine_ (turpentine) thrown upon red hot iron. In 1807 De Rivaz applied the same idea in a different manner. He employed a cylinder 12 centimeters in diameter fitted with a piston. At the bottom of the cylinder there was another smaller one, also provided with a piston. This was the aspirating cylinder, which drew hydrogen from an inflated bag, and mixed it with twice its bulk of air by means of a two-way cock. The ignition of the detonating mixture was effected by an electric spark. It is said that the inventor applied his apparatus to a small locomotive.

In 1820 Mr. Cecil, of Cambridge, proposed the employment of a mixture of air and hydrogen as a source of motive power; he gave a detailed account of his invention in the _Transactions_ of the Cambridge Philosophical Society, together with some interesting theoretical considerations. The author observes here that an explosion may be safely opposed by an elastic resistance--that of compressed air, for example--if such resistance possesses little or no inertia to be brought into play; contrariwise, the smallest inertia opposed to the explosion of a mixture subjected to instantaneous combustion is equivalent to an insurmountable obstacle. Thus a small quantity of gunpowder, or a detonating mixture of air and hydrogen, may without danger be ignited in a large closed vessel full of air, because the pressure against the sides of the vessel exerted by the explosion is not more than the pressure of the air compressed by the explosion. If a piece of card board, or even of paper, is placed in the middle of the bore of a cannon charged with powder, the cannon will almost certainly burst, because the powder in detonating acts upon a body in repose which can only be put in motion in a period of time infinitely little by the intervention of a force infinitely great. The piece of paper is therefore equivalent to an insurmountable obstacle. Of all detonating mixtures, or explosive materials, the most dangerous for equal expansions, and the least fitted for use as motive power, are those which inflame the most rapidly. Thus, a mixture of oxygen and hydrogen, in which the inflammation is produced instantaneously, is less convenient for this particular usage than a mixture of air and hydrogen, which inflames more slowly. From this point of view, ordinary gunpowder would make a good source of motive power, because, notwithstanding its great power of dilatation, it is comparatively slow of ignition; only it would be necessary to take particular precautions to place the moving body in close contact with the powder. Cecil pointed out that while a small steam engine could not be started in work in less than half an hour, or probably more, a gas engine such as he proposed would have the advantage of being always ready for immediate use. Cecil's engine was the first in which the explosive mixture was ignited by a simple flame of gas drawn into the cylinder at the right moment. In the first model, which was that of a vertical beam engine with a long cylinder of comparatively small diameter, the motive power was simply derived from the descent of the piston by atmospheric pressure; but Mr. Cecil is careful to state that power may also be obtained directly from the force of the explosion. The engine was worked with a cylinder pressure of about 12 atmospheres, and the inventor seems to have recognized that the noise of the explosions might be an objection to the machine, for he suggests putting the end of the cylinder down in a well, or inclosing it in a tight vessel for the purpose of deadening the shock.

It is interesting to rescue for a moment the account of Mr. Cecil's invention from the obscurity into which it has fallen--obscurity which the ingenuity of the ideas embodied in this machine does not merit. It is probable that in addition to the imperfections of his machinery, Mr. Cecil suffered from the difficulty of obtaining hydrogen at a sufficiently low price for use in large quantities. It does not transpire that the inventor ever seriously turned his attention to the advantages of coal gas, which even at that time, although very dear, must have been much cheaper than hydrogen. Knowing what we do at present, however, of the consumption of gas by a good engine of the latest pattern, it may be assumed that a great deal of the trouble of the gas engine builders of 60 years ago arose from the simple fact of their being altogether before their age. Of course, the steam engine of 1820 was a much more wasteful machine, as well as more costly to build than the steam engine of to-day; but the difference cannot have been so great as to create an advantage in favor of an appliance which required even greater nicety of construction. The best gas-engine at present made would have been an expensive thing to supply with gas at the prices current in 1820, even if the resources of mechanical science at that date had been equal to its construction; which we know was not the case. Still, this consideration was not known, or was little valued, by Mr. Cecil and his contemporaries. It was not long, however, before Mr. Cecil had to give way before a formidable rival; for in 1823 Samuel Brown brought out his engine, which was in many respects an improvement upon the one already described. It will probably be right, however, to regard the Rev. Mr. Cecil, of Cambridge, as the first to make a practicable model of a gas-engine in the United Kingdom.--_Journal of Gas Lighting_.

* * * * *

Alabama has 2,118 factories, working 8,248 hands, with a capital invested of $5,714,032, paying annually in wages $2,227,968, and yielding annually in products $13,040,644.

* * * * *

THE MOVING OF LARGE MASSES.

[Footnote: For previous article see SUPPLEMENT 367.]

The moving of a belfry was effected in 1776 by a mason who knew neither how to read nor write. This structure was, and still is, at Crescentino, upon the left bank of the Po, between Turin and Cazal. The following is the official report on the operation:

"In the year 1776, on the second day of September, the ordinary council was convoked, ... as it is well known that, on the 26th of May last, there was effected the removal of a belfry, 7 trabucs (22.5 m.) or more in height, from the church called _Madonna del Palazzo_, with the concurrence and in the presence and amid the applause of numerous people of this city and of strangers who had come in order to be witnesses of the removal of the said tower with its base and entire form, by means of the processes of our fellow-citizen Serra, a master mason who took it upon himself to move the said belfry to a distance of 3 meters, and to annex it to a church in course of construction. In order to effect this removal, the four faces of the brick walls were first cut and opened at the base of the tower and on a level with the earth. Into the apertures from north to south, that is to say in the direction that the edifice was to take, there were introduced two large beams, and with these there ran parallel, external to the belfry and alongside of it, two other rows of beams of sufficient length and extent to form for the structure a bed over which it might be moved and placed in position in the new spot, where foundations of brick and lime had previously been prepared.

"Upon this plane there were afterward placed rollers 3½ inches in diameter, and, upon these latter, there was placed a second row of beams of the same length as the others. Into the eastern and western apertures there were inserted, in cross-form, two beams of less length.

"In order to prevent the oscillation of the tower, the latter was supported by eight joists, two of these being placed on each side and joined at their bases, each with one of the four beams, and, at their apices, with the walls of the tower at about two-thirds of its height.

"The plane over which the edifice was to be rolled had an inclination of one inch. The belfry was hauled by three cables that wound around three capstans, each of which was actuated by ten men. The removal was effected in less than an hour.

"It should be remarked that during the operation the son of the mason Serra, standing in the belfry, continued to ring peals, the bells not having been taken out.

"Done at Crescentino, in the year and on the day mentioned."

A note communicated to the Academie des Sciences at its session of May 9, 1831, added that the base of the belfry was 3.3 m. square. This permits us to estimate its weight at about 150 tons.

Fig. 1 shows the general aspect of the belfry with its stays. This is taken from an engraving published in 1844 by Mr. De Gregori, who, during his childhood, was a witness of the operation, and who endeavored to render the information given by the official account completer without being able to make the process much clearer.

In 1854 Mr. Victor Place moved overland, from Nineveh to Mosul, the winged bulls that at present are in the Assyrian museum of the Louvre, and each of which weighs 32 tons. After carefully packing these in boxes in order to preserve them from shocks, Place laid them upon their side, having turned them over, by means of levers, against a sloping bank of earth That he afterward dug away in such a manner that the operation was performed without accident. He had had constructed an enormous car with axles 0.25 m. in diameter, and solid wheels 0.8 m. in thickness (Fig. 2). Beneath the center of the box containing the bull a trench was dug that ran up to the natural lever of the soil by an incline. This trench had a depth and width such that the car could run under the box while the latter was supported at two of its extremities by the banks. These latter were afterward gradually cut away until the box rested upon the car without shock. Six hundred men then manned the ropes and hauled the car with its load up to the level of the plain. These six hundred men were necessary throughout nearly the entire route over a plain that was but slightly broken and in which the ground presented but little consistency.

The route from Khorsabad to Mosul was about 18 kilometers, taking into account all the detours that had to be made in order to have a somewhat firm roadway. It took four days to transport the first bull this distance, but it required only a day and a half to move the other one, since the ground had acquired more compactness as a consequence of moving the first one over it, and since the leaders had become more expert. The six hundred men at Mr. Place's disposal had, moreover, been employed for three months back in preparing the route, in strengthening it with piles in certain spots and in paving others with flagstones brought from the ruins of Nineveh. In a succeeding article I shall describe how I, a few years ago, moved an ammunition stone house, weighing 50 tons, to a distance of 35 meters without any other machine than a capstan actuated by two men.--_A. De Rochas, in La Nature_.

* * * * *

[NATURE.]

SCIENCE AND ENGINEERING.