REPORT OF EXPERIMENTS ON THE EXPLOSIONS OF STEAM-BOILERS, which furnished the nitrogen gas, before referred to as issuing from the boiler, was not derived from the water injected. The injection of one fluid ounce and a quarter troy (2.25 cubic inches) of water, never gave less than 2.6 cubic inches of gas, and sometimes, notwithstanding the leakage, gave 17.28 cubic inches. But water absorbs, according to Saussure, from 5 to 51 per cent. of its bulk of atmospheric air, giving for 225 cubic inches only 118 of a cubic inch of air, not one-twentieth part of the minimum quantity of gas derived from the boiler by the injection of 2.25 cubic inches of water. On observing closely the cracked glass plate, it was seen, that after a certain period in the production of steam by the water thrown into the boiler, the vapour ceased to issue through the crack, and, finally, that a bending inwards of the pieces of glass indicated that the pressure within the boiler was less than that without, and that atmospheric air had access to the 187 interior. As no inflammable gas had as yet been obtained, and as the gas which issued was nitrogen mixed with oxygen, the entrance of air into the boiler was obviously the source of the gas collected. A new glass plate was substituted on the third day for the broken one, and a copper plate was screwed upon the opposite opening of the boiler, which was thus rendered as tight as the nature of the apparatus permitted. The experiments were made at regular intervals, varying in different parts of the series from 60 to 10 seconds, and in such a manner that the bottom of the boiler might be found in nearly the same state, in some of the experiments, with each interval. The interval was counted from the time at which gas ceased to issue in a previous experiment, The unit to the instant of injecting water. of measure of the gas was 18 cubic inches. The results were as follows: In this series we remark, first, that the mean result for an interval of 60 seconds, is 8.5 measures; for an interval of 30 seconds, 9.1 measures; for 20 seconds, 7.5 measures; and for 10 seconds, 6.9 measures. If atmospheric air leak into the boiler, the air will enter until the pressure within and without become equal. Hence an increase in the interval between two experiments in which the air should be expelled, would, above a certain point, be attended with no increase in the quantity of gas which would be expelled; the only effect being to consume, more completely, the oxygen of the entering air. Up to this point an increase of interval should be attended by an increase of air which would leak in, and consequently by an increase in the amount subsequently ex 20 10 60 pelled. The mean results given above do, in fact, show an increase in the quantity of gas obtained after an interval of 20 seconds over that obtained for 10 seconds; of 30 seconds over 20 seconds. They give a slight decrease from the interval of 30 seconds to 60 seconds, which will find its explanation on a further examination of the results. Second; we observe from the table, that after a number of short intervals, the succeeding long interval never gave as much gas as when the long interval had been repeated; and, vice versa, that after a series of long intervals, the next succeeding short interval gave a higher result than that which followed. The experiments, with an interval of 30 seconds, were not as much interspersed among the short intervals, in the last part of * The numbers marked (†) signify that an unmeasured portion of the gas escaped. 188 REPORT OF EXPERIMENTS ON THE EXPLOSIONS OF STEAM-BOILERS. the series, as were those of 60 seconds; the mean of the results for this latter interval is, therefore, diminished. No increase in the amount of gas was ob. tained by increasing the quantity of water injected. The mean of four experiments, when the bottom was at a glowing red heat, and the thermometer 7 inches from the bottom, at from 553° to 559° Fah., was 5:75 measures for 1 ounces of water; from 5720 to 580°, by the same thermometer, 10.5 measures for the same quantity of water injected; above the range of the scale of the same thermometer, 12 measures for ounces, and about the same quantity for 2 ounces. During these experiments, mercury, which was on the top of the boiler, in a clay receptacle, boiled freely. The best evidence is thus given that the bottom of the boiler was not wanting in heat; it was, in fact, at a bright red heat during the last part of the experiments. The peculiar odour, before remarked, as belonging to the gas expelled from the boiler, still continued, indicating the presence of sediment within the boiler; this could be seen when the metal was glowing. A scale of oxide also appeared on the bottom, which now and then cracked, presenting irregular luminous lines as the boundaries of the scale. The experiments just detailed were, on a succeeding day, repeated, to ascertain whether the same results would be reproduced. The bottom of the boiler being at a bright red heat, an interval of 60 seconds gave, as the mean of four experiments, 11.5 measures of gas for one ounce of water injected ; an interval of 30 seconds gave, as the mean of five experiments with three-fourths of an ounce of water, 13 measures; an interval of 20 seconds gave, as the mean of four experiments with half an ounce of water, 10.6 measures and again, in a second series, the same interval gave 105 measures for the mean of four experiments with five-eighths of an ounce of water. Towards the close, the numbers for 10 seconds of interval were very variable, the mean of six experiments with '65 ounces of water, injected when the boiler was at a cherry red, was 63 measures, of gas; with a heat which, to all appearance, was the same, the gas collected diminished to 3.5 mea. sures, and averaged 33 measures at a bright red heat. For an interval of 5 seconds, with 1 ounces of water injected, 44 measures of gas were obtained. The conclusions to be drawn from these results agree with those already deduced from the previous experiments, which were thus confirmed. The gas collected was carefully transferred, over water, to the laboratories, where it was analysed. One specimen yielded Professor Hare, nitrogen with seven per cent. of oxygen; another, examined by Professor A. D. Bache, gave ni trogen, and 9 per cent. of oxygen in each case the results were obtained by exploding a mixture of the gas with hydrogen. The boiler was now thoroughly cleansed, that the scale of oxide upon the bottom might be removed; in doing this, the handhole was necessarily removed, and had to be repacked. Paper was placed between the glass plate at the back end of the boiler and its metallic covering, that the boiler might ve tightened. To ascertain the amount and direction of the current setting into, or out of, the boiler at any time, a copper pipe, terminating in a glass tube, was attached to one of the stop-cocks on the head, at the fire end of the boiler, the glass tube dipping into a vessel containing water. The injection water was, on resuming the experiments, heated over a small furnace, to boiling, in a metallic vessel, from which it was drawn by the pump. When the bottom of the boiler was at a bright red heat, the lowest thermometer had attained a temperature of 570°, and was soon after removed. The quantity of water thrown in at each stroke of the pump, was now by no means so regular as when the action of the pump was not impeded by the formation of steam within it, from the injection water. results obtained were: The visibly di minished by water in jected. Bright red. Experiments made after a rest. Gas puts out candle. Bright red. Do. Do. Do. Do. Gas burned at mouth of jar with a blue flame. Gas burns with blue flame. now A combustible gas had appeared for the first time. The injection water was changed for cold water, and a gas obtained, which burned as before; 11 measures of air and one measure of the gas detonated slightly, also one to 8 measures of air; neither detonation was sufficiently violent to extinguish the candle held at the mouth of the jar in which the gases were fired. The gas now came over, not in copious bubbles and during a short time, but slowly and continuously, as if resulting from a constant, but not violent, chemical action. After these results had been obtained, the violent and brief bubbling, when the water was injected, recommenced, and the combustible gas was no more obtained. The REPORT OF EXPERIMENTS ON THE EXPLOSIONS OF STEAM-BOILERS. 189 change of hot injecting water for cold, and the collection of the combustible gas after the change, showed that the gas was not derived from any effect produced by the increased temperature of the liquid introduced. The other circumstances which had been different from those of former experiments, were the superior cleanliness of the bottom of the boiler, and the repacking of the hand hole with cloth, oil and putty, and of the glass window with paper. Before proceeding to the detail of the experiments, in examination of the source of the combustible gas obtained, it may be well to mention that the glass tube, already spoken of, showed, after the water injected in some of the experiments had evaporated, a current of air, due to a force equivalent to a head of from to 1 inches of water, from the exterior into the boiler; in one experiment it is noted that the water, in the tube referred to, soon fell, which indicated a leak in some part of the boiler. On the day following that upon which the experiments just given were made, nothing conclusive was obtained; no combustible gas appeared, but the heat was hardly as high as Appearance of Boiler. on the preceding day. Small disks of wood, thrown into the boiler, gave a combustible gas, which came over just as was noticed in relation to the inflammable gas of the preceding day's experiments. That these inflammable gases, in mixture with the oxygen, remaining in the atmospheric air within the boiler, produced no explosion. is in accordance with the well-known fact in relation to them; pure hydrogen, in such a mixture, combines with oxygen under the influence of a body heated to redness. On the following day of experiment, circumstances proved entirely favourable; the bottom of the boiler was heated as intensely as on the former occasion. After much incombustible gas had been obtained, traces of an inflammable one appeared. A strong smell of oil was noticed about the hand hole, at the back end of the boiler; the packings were now white on the exterior. The fire was urged, and the boiler became strongly heated throughout its whole length. The following results are from the journal of the experiments: No. of measures of gas. REMARKS. Candle burns feebly in gas. A piece of paper put against back hand hole is charred. Wood put at back end of boiler (out. side) charred. Paper browns on top. Gas puts out candle. Gas puts out candle. 8 7호 Wood chars at fire end (outside) being the less heated end. Gas extinguishes candle, and does not burn. No combustible gas was procured in these experiments, though the circumstances were more favourable to the production of hydrogen, by the boiler, than on other occasions. On examining the cloth packing of the hand holes at each end, it was found to have disappeared, except in spots; the putty was white. The boiler was not dirty enough to colour, with oxide of iron, clean water which was introduced. These results point conclusively to the packing, as the source of the combustible gas No smell of oil gas. Wood at both ends charring. Paper on top of boiler charring. obtained. The flame of that gas was that of carburetted hydrogen, and not of pure hydrogen. They further show that even in this intensely heated state of the bottom of the boiler no hydrogen was liberated by the decomposition of the water injected. In conclusion, it appears from these experiments: 1. That the gas obtained by injecting water upon the bottom of a boiler which was at a bright red heat was nitrogen gas, with a variable quantity of oxygen: it was, in fact, 190 RECENT AMERICAN PATENTS. atmospheric air deprived, by the heated metal, of more or less of its oxygen. 2. That this air was derived, principally, from the current into the boiler when surcharged steam had ceased to be formed, and the boiler was left dry; there will, therefore, be no such quantity in a working boiler, where the air must be supplied from the cold water thrown in. 3. That water in contact with heated iron in a steam boiler, the surface being in its ordinary state, clean, but not bright, is not decomposed by the metal. (To be continued in our next.) RECENT AMERICAN PATENTS. (Selected from the Franklin Journal, for May.) IMPROVED DOUBLE SPEEDER, William Field, Rhode Island. This improvement "consists in a plan of compressing the roving on the spool so hard, or compact, that the same quantity may be put on a spool of only one-fifth of the common size. A machine with this improvement will occupy only one half of the room, will require much less power, and will run at least one-third faster than common speeders." The usual plans for drawing, twisting, and winding the roving, are followed; but the spools are run faster than the flyers, to take up the roving, instead of permitting them to fall back, in the common manner. The flyers are supported wholly above and independent of the spindles, are about one-half the usual length and diameter, and have a hoop at their lower ends to prevent their expanding. The condensation of the roving is effected by the pressure of a thin circular plate against it, as it is wound on the spool; the plate being about the same diameter as the spool. The claims are to "the plan of compressing roving on spools by circular plates, hav-. ing a rotary motion, acquired by their pressure on the spools, the edges of which act on the roving as it is received from the flyers, and thereby condense it, so that a much greater quantity can be deposited on spools of the same size. The sliding rail in the rear of the spools, on which the circular plates are placed, and the connexion between the increasing size of the spools, and the traverse motion of the belt guide, so that the spools may cause the variation of speed which their constantly increasing size requires. The application of a heart motion for traversing the spools, so formed as to cause them to rise with greater velocity than they fall, so that a less quantity of roving may be deposited on the spools when rising than when falling." DISTILLING ALCOHOL FROM APPLES, Anson Walcott, New York.-The pommage is to be put into a steam-tight tub, into which steam is to be admitted through a tube, which descends nearly to the bottom of it; a series of vessels, similarly connected by tubes, and perfectly resembling Woulfe's apparatus, is terminated by a condensing worm. The three last vessels, as represented, are to be hollow globes of metal, placed within open tubs, the water in which is to be sufficiently warm to keep the alcohol in the state of vapour, as, otherwise, it would condense in the hollow globes. The claim is to "the application of steam in extracting alcohol from apple pommage, without first making it into cider, aud the globular metallic condensers." SAFETY STEAM-ENGINE BOILER, John C.F. Saloman, Reading, Pennsylvania.-The claim under this patent is to "the principle of constructing boilers with inverted arches, so arranged as that their convex surfaces shall resist the pressure of the steam; and the surrounding of the boiler so formed by a cylindrical or polygonal casing, forming a chord to each arch the whole length of the boiler, and thus preventing the spring of the said arches; whilst at the same time the spaces between the cases and the arches thus formed may serve as fire-places and flues for generating and conducting heat." Not only is the body of the boiler to consist of arched segments, riveted together at their edges, but the heads also are to be concave inwards, so as to be pressed on by the steam in the manner of a dome. Such a boiler would have a much less capacity in proportion to its weight than one of the cylindrical form, and there would scarcely be a single point within it which, by yielding to the internal force, when not sufficient to rupture it, would not thereby enlarge its capacity. The arched form, in a malleable, flexible substance, such as iron, will not operate in the same way with the stones in an arch of masonry; every indentation in the metal is a commencing point at which it may give way, and be followed by all the parts which surround it. Besides this, we see not how the places of juncture exposed to the action of the fire, and the metal forming the chord of the arches thus exposed, are to be kept from heating, and burning out. The thing at first view is specious in its appearance, but it will not stand the test of examination, or the still more searching one of fire. APPLICATION OF HYDRAULIC POWER, Robert Mills and H. B. Fernald, Portland.The rising and falling of the tide is to be employed for the purpose of condensing atmo MR. HANCOCK'S STEAM-CArriages. spheric air, which condensed air is to be afterwards applied as a motive power, to machinery. The mode of condensing consists in placing a reservoir in the water, which shall rest on the bottom. This reservoir is to be open at bottom, to admit the water, but closed at top, to retain the air; the top is to rise to a convenient height above the line of high water; at this line there must be a horizontal partition, or diaphragm, furnished with valves, opening upwards, to admit the air as the water rises, and to retain it in the air-chamber when it falls. This chamber is to be "provided with suitable screw-valves, to admit of using the condensed air at pleasure;" it is to be "applied like steam." "In the falling of the water, there will be a vacuum created, or a tendency to that effect, in the air-chamber, or room; and the atmosphere being admitted through a valve, opening inward, will rush with a force proportionable to the base of the airroom, or chamber, and thus a power will be gained, in the falling of the tide, or water, which may also be employed to condense more air, or otherwise, by making the pressure of this air to work a wheel, or piston, as it enters the air-chamber." We noticed a patent, obtained, about two months since, by one of the above-named gentlemen, for applying the rising and falling of the tide to the propelling of machinery, and showed that the plan then proposed was old, referring to a former patent for the same thing, and our remarks thereon. Although the mode there proposed is not, we think, likely to come into extensive use, there are situations where the power obtainable might be usefully applied; but if that now brought forward is intended as an improvement thereon, we are very certain that the thing will be "mended worse." To use the condensed air to advantage, would be an undertaking of great practical difficulty, and, in the present case, could not be effected, but by a very considerable loss of power; the patentees, however, have furnished us with no plan for doing this, and we will not attack windmills. We do not know even what they mean by " screw-valves;" these are certainly novelties in mechanics. There is no point more clearly ruled than that a patent cannot be sustained for a principle, but only for the carrying of a principle into effect by certain means; but, in the case before us, no means are given.* CALENDERING CLOTH, Zenas Bliss John-ston. Rhode Island.-The improvement here patented consists in the addition of a roller above the three ordinarily used in calenders, by the aid of which additional roller the cloth * See Mech. Mag., vol. xvi. pp. 375 and 436. 191 is twice glazed in its passage between the rollers, thereby preventing the necessity of performing the operation a second time. In the ordinary calender, it is said that the boxes in which the gudgeons of the top roller run, last generally but sixty days, the weight having to be applied on them, whilst by the new arrangement, in which a large roller with a slow motion receives the weight, the boxes will last for two years. MANUFACTURE OF TUBES AND HINGES, William Shaw, Buffalo.-The machine intended to be described is one for bending sheet metal to form the tubular knuckles of hinges; the description is a very imperfect one, and there is not any claim made; we think, however, so far as the materials before us will justify an opinion, that the machine is sufficiently original to be claimed as a whole. The sheet metal is to be passed in between two blocks of steel, and held in its place by a tightening screw; when, by turning a crank, the end of it is bent round a pin, which pin is to be pushed out by placing the hand upon a lever, thus forcing up a round punch, or wire, for that purpose. ARTIFICIAL STONE, &c., Charles Clinton, New York.-Limestone is to be burnt until about two-fifths of it is converted into lime; to four bushels of this, when cool, four pounds of pearl-ash and three pounds of alum are to be added, and the whole ground fine; the composition is to be put into open barrels, and to remain there until the lime is perfectly slacked, after which it is to be mixed with water to a proper consistence, and used as a hard finish for walls; when rubbed down, it is to look like polished mar ble. For outside walls, about one-third part of sand is to be added. The composition may be variegated in its colours by the addition of proper materials for that purpose, and a variety of modes are suggested for varying the ornamental appearance of it. "Blocks, pillars, &c., may be formed of the cement, and, when sufficiently dry, may be plastered, as before directed, and polished." 116 MR. HANCOCK'S STEAM-CARRIAGES. Statement of One Month's Performances on the Paddington-road, from May 16 to June 15. 42 trips from the City to Paddington. Islington. Number of passengers carried ..2970. On the occasion of the opening of Moorgate-street by the Lord Mayor, on Monday last, the "Enterprise" entered immediately after the train of Aldermen, when one of the City officers mounted the roof, waving a large flag. The steamer was full of passengers, and loudly cheered by the populace. |