Chapter 2

The time and opportunity has now arrived to assert before all the world the American origin of these universally beneficent inventions. Such a demonstration should be made, if only for the instruction of the rising generation. Not a school book has fallen into the hands of the writer that correctly sets forth the origin of the subject matter of this paper. He apprehends that it is the same with the books used in colleges and universities, for otherwise how could that parody on the history of the locomotive, called "The Life of George Stephenson, Railway Engineer," by Samuel Smiles, have met such unbounded success? To the amazement of the writer, a learned professor in one of the most important institutions of learning in the country did, in a lecture, quote Smiles as authority on a point bearing on the history of the locomotive! It is true that he made amends by adding, when his lecture was published, a counter statement; but that such a man should have seriously cited such a work shows the widespread mischief done among people not versed in engineering lore by the admirably written romance of Smiles, who as Edward C. Knight, in his Mechanical Dictionary, truly declares, has "pettifogged the whole case." If, as Prof. Renwick intimates, "conflicting national pride" has led the major part of British writers to suppress the truth as to the origin of the high pressure steam engine, the locomotive, and the steam railway system, surely true national pride should induce the countrymen of Oliver Evans to assert it. In closing this paper the writer will say, for the information of the so-called "practical" men of the country, or, in other words, those men whose judgment of an invention is mainly guided by its money value, that Poor's Manual of Railroads in the United States for 1886 puts their capital stock and their debts at over $8,162,000,000. The value of the steamships and steamboats actuated by the high pressure steam engine the writer has no means of ascertaining. Neither can he appraise the factories and other plants in the United States--to say nothing of the rest of the world--in which the high pressure steam engine forms the motive power.

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AUGUSTE'S ENDLESS STONE SAW.

It does not seem as if the band or endless saw should render the same services in sawing stone as in working wood and metals, for the reason that quite a great stress is necessary to cause the advance of the stone (which is in most cases very heavy) against the blade. Mr. A. Auguste, however, has not stopped at such a consideration, or, better, he has got round the difficulty by holding the block stationary and making the blade act horizontally. Fig. 1 gives a general view of the apparatus; Fig. 2 gives a plan view; Fig. 3 is a transverse section; Fig. 4 is an end view; Figs. 5, 6, and 7 show details of the water and sand distributer; and Figs. 8, 9, and 10 show the pulleys arranged for obtaining several slabs at once.

The machine is wholly of cast iron. The frame consists of four columns, A, bolted to a rectangular bed plate, A', and connected above by a frame, B, that forms a table for the support of the transmission pieces, as well as the iron ladders, _a_, and the platform, _b_, that supports the water reservoirs, C, and sand receptacles, C'.

Between the two columns at the ends of the machine there are two crosspieces, D and D', so arranged that they can move vertically, like carriages. These pieces carry the axles of the pulleys, P and P', around which the band saw, S, passes. In the center of the bed plate, A', which is cast in two pieces connected by bolts, there are ties to which are screwed iron rails, _e_, which form a railway over which the platform car, E, carrying the stone is made to advance beneath the saw.

The saw consists of an endless band of steel, either smooth or provided with teeth that are spaced according to the nature of the material to be worked. It passes around the pulleys, P and P', which are each encircled by a wide and stout band of rubber to cause the blade to adhere, and which are likewise provided with two flanges. Of the latter, the upper one is cast in a piece with the pulley, and the lower one is formed of sections of a circle connected by screws. The pulley, P, is fast, and carries along the saw; the other, P', is loose, and its hub is provided with a bronze socket (Figs. 1 and 4). It is through this second pulley that the blade is given the desired tension, and to this effect its axle is forged with a small disk adjusted in a frame and traversed by a screw, _d'_, which is maneuvered through a hand wheel. The extremities of the crosspieces, D and D', are provided with brass sockets through which the pieces slide up and down the columns, with slight friction, under the action of the vertical screws, _g_ and _g'_, within the columns.

A rotary motion is communicated to the four screws simultaneously by the transmission arranged upon the frame. To this effect, the pulley, P, which receives the motion and transmits it to the saw, has its axle, _f_, prolonged, and grooved throughout its length in order that it may always be carried along, whatever be the place it occupies, by the hollow shaft, F, which is provided at the upper extremity with a bevel wheel and two keys placed at the level of the bronze collars of its support, G. The slider, D, is cast in a piece with the pillow block that supports the shaft, _f_, and the bronze bushing of this pillow block is arranged to receive a shoulder and an annular projection, both forged with the shaft and designed to carry it, as well as the pulley, P, keyed to its extremity. Now the latter, by its weight, exerts a pressure which determines a sensible friction upon the bushing through this shoulder and projection, and, in order to diminish the same, the bushing is continuously moistened with a solution of soap and water through the pipe, _g_, which runs from the reservoir, G'.

The saw is kept from deviating from its course by movable guides placed on the sliders, D and D'. These guides, H and H', each consist of a cast iron box fixed by a nut to the extremity of the arms, _h_ and _h'_, and coupled by crosspieces, _j_ and _j'_, which keep them apart and give the guides the necessary rigidity.

The shaft, _m_, mounted in pillow blocks fixed to the left extremity of the frame, receives motion from the motor through the pulley, _p_, at the side of which is mounted the loose pulley, _p_. This motion is transmitted by the drum, M, and the pulley, L, to the shaft, _l_, at the other extremity. This latter is provided with a pinion, _l'_, which, through the wheel, F', gives motion to the saw. The shaft, _m_, likewise controls the upward or downward motion of the saw through the small drums, N and _n_, and the two pairs of fast and loose pulleys, N' and _n'_. This shaft, too, transmits motion (a very slow one) to the four screws, _g_ and _g'_, in the interior of the columns, and the nuts of which are affixed to the sliders, D and D'. To this effect, the shaft, _q_, is provided at its extremities with endless screws that gear with two wheels, _q_', with helicoidal teeth fixed near the middle of two parallel axes, _r_, running above the table, B, and terminating in bevel wheels, _r'_, that engage with similar wheels fixed at the end of the screws, _g_ and _g'_.

The car that carries the block to the saw consists of a strong frame, E, mounted upon four wheels. This frame is provided with a pivot and a circular track for the reception of the cast iron platform, E', which rests thereon through the intermedium of rollers. Between the rails, _e_, and parallel with them, are fixed two strong screws, _e'_, held by supports that raise them to the bottom of the car frame, so that they can be affixed thereto. When once the car is fastened in this way, the screws are revolved by means of winches, and the block is thus made to advance or recede a sufficient distance to make the lines marked on its surface come exactly opposite the saw blade.

In sawing hard stones, it is necessary, as well known, to keep up a flow of water and fine sand upon the blade in order to increase its friction. Upon two platforms, _b_, at the extremities of the machine, are fixed the water reservoir, C, and the receptacles, C', containing fine sand or dry pulverized grit stone. As may be seen from Figs. 5 and 6, the bottom of the sand box, C', is conical and terminates in a hopper, T, beneath which is adjusted a slide valve, _t_, connected with a screw that carries a pulley, T'. By means of this valve, the bottom of the hopper may be opened or closed in such a way as to regulate the flow of the sand at will by acting upon the pulley, T', through a chain, _t'_, passing over the guide pulley, _t²_. A rubber tube, _u_, which starts from the hopper, runs into a metal pipe, U, that descends to the guide, H, with which it is connected by a collar. Under the latter, this pipe terminates in a sphere containing a small aperture to allow the sand to escape upon an inclined board provided with a flange. At the same time, through the rubber tube, _c_, coming from the reservoir, C, a stream of water is directed upon the board in order to wet the sand.

As the apparatus with but a single endless saw makes but two kerfs at once, Mr. Auguste has devised an arrangement by means of which several blades may be used, and the work thus be expedited.

Without changing the general arrangements, he replaces the pulleys, P and P', by two half drums, V and V' (Figs. 8, 9, and 10), which are each cast in a piece with the crosspieces, D² and D³, designed to replace D and D', and, like them, sliding up and down the columns, A, of the frame. Motion is transmitted to all the saw blades by a cog wheel, X, keyed to the vertical shaft, _f_, and gearing with small pinions, _x_, which are equally distant all around, and which themselves gear with similar pinions forming the radii of a succession of circles concentric with the first. All these pinions are mounted upon axles traversing bronze bearings within the drum, which, to this effect, is provided with slots. The axles of the pinions are prolonged in order to receive rollers, _x'_, surrounded with rubber so as to facilitate, through friction, the motion of all the blades running between them.

The other drum, V', is arranged in the same way, except that it is not cast in a piece with the carriage, D³, but is so adjusted to it that a tension may be exerted upon the blades by means of the screw, _d_, and its hand wheel.

Through this combination, all the blades are carried along at once in opposite directions and at the same speed.--_Publication Industrielle._

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ROBURITE, THE NEW EXPLOSIVE.

A series of experiments of great interest and vital importance to colliery owners and all those engaged in mining coal has been carried out during the last ten days in the South Yorkshire coal field. The new mines regulation act provides that any explosible used in coal mines shall either be fired in a water cartridge or be of such a nature that it cannot inflame firedamp. This indeed is the problem which has puzzled many able chemists during the last few years, and which Dr. Roth, of Berlin, claims to have solved with his explosive "roburite." We recently gave a detailed account of trials carried out at the School of Military Engineering, Chatham, to test the safety and strength of roburite, as compared with gun cotton, dynamite, and blasting gelatine. The results were conclusive of the great power of the new explosive, and so far fully confirmed the reports of the able mining engineer and the chemical experts who had been sent to Germany to make full inquiries. These gentlemen had ample opportunity of seeing roburite used in the coal mines of Westphalia, and it was mainly upon their testimony that the patents for the British empire were acquired by the Roburite Explosive Company.

It has, however, been deemed advisable to give practical proof to those who would have to use it, that roburite possesses all the high qualities claimed for it, and hence separate and independent trials have been arranged in such representative collieries as the Wharncliffe Silkstone, near Sheffield, Monk Bretton, near Barnsley, and, further north, in the Durham coal field, at Lord Londonderry's Seaham and Silksworth collieries. Mr. G.B. Walker, resident manager of the Wharncliffe Colliery Company, had gone to Germany as an independent observer--provided with a letter of introduction from the Under Secretary of State for Foreign Affairs--and had seen the director of the government mines at Saarbruck, who gave it as his opinion that, so far as his experience had gone, the new explosive was a most valuable invention. Mr. Walker was so impressed with the great advantages of roburite that he desired to introduce it into his own colliery, where he gladly arranged with the company to make the first coal mining experiments in this country. These were recently carried out in the Parkgate seam of the Wharncliffe Silkstone colliery, under the personal superintendence of the inventor, Dr. Roth, and in the presence of a number of colliery managers and other practical men.

In all six shots were fired, five of which were for the purpose of winning coal, while the sixth was expressly arranged as a "blowout shot." The roburite--which resembles nothing so much as a common yellow sugar--is packed in cartridges of about 4½ in. in length and 1½ in. in diameter, each containing about 65 grammes (one-seventh of a pound) inclosed in a waterproof envelope. By dividing a cartridge, any desired strength of charge can be obtained. The first shot had a charge of 90 grammes (one-fifth of a pound) placed in a hole drilled to a depth of about 4 ft. 6 in., and 1¾ in. in diameter. All the safety lamps were carefully covered, so that complete darkness was produced, but there was no visible sign of an explosion in the shape of flame--not even a spark--only the dull, heavy report and the noise made by the displaced coal. A large quantity of coal was brought down, but it was considered by most of the practical men present to be rather too much broken. The second shot was fired with a single cartridge of 65 grammes, and this gave the same remarkable results as regards absence of flame, and, in each case, there were no noxious fumes perceivable, even the moment after the shot was fired. This reduced charge gave excellent results as regards coal winning, and one of the subsequent shots, with the same weight of roburite, produced from 10 to 11 tons of coal in almost a solid mass.

It has been found that a fertile cause of accidents in coal mines is insufficient tamping, or "stemming," as it is called in Yorkshire. Therefore a hole was bored into a strong wall of coal, and a charge of 45 grammes inserted, and very slightly tamped, with the view of producing a flame if such were possible. This "blowout" shot is so termed from the fact of its being easier for the explosion to blow out the tamping, like the shot from a gun, than to split or displace the coal. The result was most successful, as there was no flash to relieve the utter darkness.

The second set of experiments took place on October 24 last, in the Monk Bretton colliery, near Barnsley, of which Mr. W. Pepper, of Leeds, is owner. This gentleman determined to give the new explosive a fair and exhaustive trial, and the following programme was carried out in the presence of a very large gathering of gentlemen interested in coal mining. The chief inspector of mines for Yorkshire and Lincolnshire, Mr. F.N. Wardell, was also present, and the Roburite Explosives Company was represented by Lieut.-General Sir John Stokes, K.C.B., R.E., chairman, and several of the directors.

1. _Surface Experiments._--A shot fired on the ground, exposed. This gave no perceptible flame (70 grammes of roburite was the charge in these experiments).

2. A shot fired on the ground, bedded in fine coal dust. No flame nor ignition of the coal dust was perceptible.

3. A shot fired suspended in a case into which gas was conducted, and the atmospheric air allowed to enter so as to form an explosive mixture. The gas was not fired.

4. A shot fired in a boiler flue 16 ft. by 2 ft. 8 in., placed horizontally, in which was a quantity of fine coal dust kept suspended in the air by the action of a fan. No flame nor ignition of the coal dust took place.

5. A shot fired as above, except that an explosive mixture of gas and air was flowing into the boiler tube in addition to the coal dust. That this mixture was firedamp was proved by the introduction of a safety lamp, the flame of which was elongated, showing what miners call the "blue cap." There was no explosion of the gas or sign of flames.

6. A shot of roburite fired in the boiler tube without any gas or suspended coal dust. The report was quite as loud as in the preceding case; indeed, to several present it seemed more distinct.

7. A shot of ½ lb. gunpowder was fired under the same condition as No. 5, i.e., in an explosive mixture of gas and air with coal dust. The result was most striking, and appeared to carry conviction of the great comparative safety of roburite to all present. Not only was there an unmistakable explosion of the firedamp, with very loud report, and a vivid sheet of flame, but the gas flowing into the far end of the boiler tube was ignited and remained burning until turned off.

_In the Pit._--1. A 2 in. hole was drilled 4 ft. 6 in. deep into coal, having a face 7 yards wide, fast at both ends, and holed under for a depth of 8 ft., end on, thickness of front of coal to be blown down 2 ft. 10 in., plus 9 in. of dirt. This represented a most difficult shot, having regard to the natural lines of cleavage of the coal--a "heavy job" as it was locally termed. The charge was 65 grammes of roburite, which brought down a large quantity of coal, not at all too small in size. No flame was perceptible, although all the lamps were carefully covered.

2. A 2 in. hole drilled 4 ft. 6 in. into the side of the coal about 10 in. from the top, fast ends not holed under, width of space 10 ft. This was purposely a "blowout" shot. The result was again most satisfactory, the charge exploding in perfect darkness.

3. A "breaking up" shot placed in the stone roof for "ripping," the hole being drilled at an angle of 35 deg. or 40 deg. This is intended to open a cavity in the perfectly smooth roof, the ripping being continued by means of the "lip" thus formed. The charge was 105 grammes (nearly 4 oz), and it brought down large quantities of stone.

4. A "ripping" shot in the stone roof, hole 4 ft. 6 in. deep, width of place 15 ft. with a "lip" of 2 ft. 6 in. This is a strong stone "bind," and very difficult to get down. The trial was most successful, a large heap of stone being brought down and more loosened.

5. A second "blowout" shot, under the conditions most likely to produce an accident in a fiery mine. A 2 in. hole, 4 ft. 6 in. deep, was drilled in the face of the coal near the roof, and charged with 105 grammes of roburite. A space of 6 in. or 8 in. was purposely left between the charge and the tamping. The hole was then strongly tamped for a distance of nearly 2 ft. The report was very loud, and a trumpet-shaped orifice was formed at the mouth of the hole, but no flame or spark could be perceived, nor was any inconvenience caused by the fumes, even the instant after the explosion.

_Further Experiments at Wharncliffe Colliery._--On Tuesday, October 25, some very interesting surface trials were arranged with great care by Mr. Walker. An old boiler flue was placed vertically, and closed at top by means of a removable wooden cover, the interior space being about 72 cubic feet. A temporary gasometer had been arranged at a suitable distance by means of a paraffin cask having a capacity of 6 cubic feet suspended inside a larger cask, and by this means the boiler was charged with a highly explosive mixture of gas and air in the proportion of 1 to 12.

1. A charge of gunpowder was placed in the closed end of a piece of gas pipe, and strongly tamped, so as to give the conditions most unfavorable to the ignition of the firedamp. It was, however, ignited, and a loud explosion produced, which blew off the wooden cover and filled the boiler tube with flame.

2. Under the same conditions as to firedamp, a charge of roburite was placed on a block of wood inside the boiler, totally unconfined except by a thin covering of coal dust. When exploded by electricity, as in the previous case, no flame was produced, nor was the firedamp ignited.

3. The preceding experiment was repeated with the same results.

4. A charge of blasting gelatine, inserted in one of Settle's water cartridges, was suspended in the boiler tube and fired with a fulminate of mercury detonator in the usual manner. The gelatine did not, however, explode, the only report being that of the detonator. After a safe interval the unexploded cartridge was recovered, or so much of it as had not been scattered by the detonator, and the gelatine was found to be frozen. This fact was also evident from an inspection of other gelatine dynamite cartridges which had been stored in the same magazine during the night. This result, although not that intended, was most instructive as regards the danger of using explosives which are liable to freeze at such a moderate temperature, and the thawing of which is undoubtedly attended with great risk unless most carefully performed. Also, the small pieces of the gelatine or dynamite, when scattered by the explosion of the detonator, might cause serious accident if trodden upon.--_Engineering._

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THE MECHANICAL REELING OF SILK.

When automatic machinery for thread spinning was invented, English intelligence and enterprise were quick to utilize and develop it, and thus gained that supremacy in textile manufacture which has remained up to the present time, and which will doubtless long continue. The making of the primary thread is the foundation of all textile processes, and it is on the possibility of doing this by automatic machinery that England's great textile industries depend. The use of highly developed machinery for spinning cotton, wool, and flax has grown to be so much a part of our conception of modern life, as contrasted with the times of our grandfathers, as often to lead to the feeling that a complete and universal change has occurred in all the textile industries. This is, however, not the case. There is one great textile industry--one of the most staple and valuable--still in the primitive condition of former times, and employing processes and apparatus essentially the same as those known and employed before such development had taken place. We mean the art of silk reeling. The improvements made in the production of threads of all other materials have only been applied to silk in the minor processes for utilizing waste; but the whole silk trade and manufacture of the world has, up to this time, been dependent for its raw silk threads upon apparatus which, mechanically speaking, is nearly or quite as primitive as the ancient spinning wheels. Thousands of operatives are constantly employed in forming up these threads by hand, adding filament by filament to the thread as required, while watching the unwinding from the cocoon of many miles of filament in order to produce a single pound of the raw silk thread, making up the thread unaided by any mechanical device beyond a simple reel on which the thread is wound as finished, and a basin of heated water in which the cocoons are placed.