Chapter X · (continued 2)

1675. Bernair attempted to fly—killed. 1678. Besnier attempted to fly. 1772. L'Abbé Desforges announced an aerial chariot. 1783. Montgolfier constructed the first air balloon. " Roberts frères, first gas balloon, destroyed by the peasantry of Geneva, who imagined it to be an evil spirit or the moon. 1784. Madame Thiblé, the first lady who was ever up in the clouds; she ascended 13,500 feet. " Duke de Chartres, afterwards Egalité Orleans, travelled 135 miles in five hours in a balloon. " Testu de Brissy, equestrian ascent. " D'Achille, Desgranges, and Chalfour—Montgolfier balloon. " Bacqueville attempted a flight with wings. " Lunardi—gas balloon. " Rambaud—Montgolfier balloon, which was burnt. " Andreani—Montgolfier balloon. 1785. General Money—gas balloon, fell into the water, and not rescued for six hours. " Thompson, in crossing the Irish Channel, was run into with the bowsprit of a ship whilst going at the rate of twenty miles per hour. " Brioschi—gas balloon ascended too high and burst the balloon; the hurt he received ultimately caused his death. " A Venetian nobleman and his wife—gas balloon—killed. " Pilatre de Rozier and M. Romain—gas balloon took fire—both killed. 1806. Mosment—gas balloon—killed. " Olivari—Montgolfier balloon—killed. 1808. Degher attempted a flight with wings. 1812. Bittorf—Montgolfier balloon—killed. 1819. Blanchard, Madame—gas balloon—killed. 1819. Gay Lussac—gas balloon, ascended 23,040 feet above the level of the sea. Barometer 12.95 inches; thermometer 14.9 Fah. " Gay Lussac and Biot—gas balloon for the benefit of science. Both philosophers returned safely to the earth. 1824. Sadler—gas balloon—killed. " Sheldon—gas balloon. " Harris—gas balloon—killed. 1836. Cocking—parachute from gas balloon—killed. 1847. Godard—Montgolfier balloon fell into and extricated from the Seine. 1850. Poitevin, a successful French aeronaut. " Gale, Lieut.—gas balloon—killed. " Bixio and Barral—gas balloon. " Graham, Mr. and Mrs.—gas balloon.—Serious accident ascending near the Great Exhibition in Hyde Park. " Green, the most successful living aeronaut of the present time.

Of the 41 persons enumerated, 14 were killed, and nearly all the aeronauts met with accidents which might have proved fatal.

Fig. 118.

Flying machine (theoretical).

Tenth Experiment.

Soap bubbles blown with hydrogen gas ascend with great rapidity, and break against the ceiling; if interrupted in their course with a lighted taper they burn with a slight yellow colour and dull report.

Eleventh Experiment.

By constructing a pewter mould in two halves, of the shape of a tolerably large flask, a balloon of collodion may be made by pouring the collodion inside the pewter vessel, and taking care that every part is properly covered; the pewter mould may be warmed by the external application of hot water, so as to drive off the ether of the collodion, and when quite dry the mould is opened and the balloon taken out. Such balloons may be made and inflated with hydrogen by attaching to them a strip of paper, dipped in a solution of wax and phosphorus, and sulphuret of carbon; as the latter evaporates, the phosphorus takes fire and spreads to the balloon; which burns with a slight report. The pewter mould must be very perfectly made, and should be bright inside; and if the balloons are filled with oxygen and hydrogen, allowing a sufficient excess of the latter to give an ascending power, they explode with a loud noise directly the fire reaches the mixed gases.

Twelfth Experiment.

In a soup-plate place some strong soap and water; then blow out a number of bubbles with a mixture of oxygen and hydrogen; a loud report occurs on the application of flame, and if the room is small the window should be placed open, as the concussion of the air is likely to break the glass.

Thirteenth Experiment.

Any noise repeated at least thirty-two times in a second produces a musical sound, and by producing a number of small explosions of hydrogen gas inside glass tubes of various sizes, the most peculiar sounds are obtained. The hydrogen flame should be extremely small, and the glass tubes held over it may be of all lengths and diameters; a trial only will determine whether they are fit for the purpose or not.

Fourteenth Experiment.

Flowers, figures, or other designs, may be drawn upon silk with a solution of nitrate of silver, and the whole being moistened with water, is exposed to the action of hydrogen gas, which removes the oxygen from the silver, and reduces it to the metallic state.

In like manner designs drawn with a solution of chloride of gold are produced in the metallic state by exposure to the action of hydrogen gas. Chloride of tin, usually termed muriate of tin, may also be reduced in a similar manner, care being taken in these experiments that the fabric upon which the letters, figures, or designs are painted with the metallic solution be kept quite damp whilst exposed to the hydrogen gas.

Fifteenth Experiment.

A mixture of two volumes of hydrogen with one volume of oxygen explodes with great violence, and produces two volumes of steam, which condense against the sides of the strong glass vessel, in which the experiment may be made, in the form of water. As the apparatus called the Cavendish bottle, by which this experiment only may be safely performed, is somewhat expensive, and requires the use of an air-pump, gas jars with stop-cocks, and an electrical machine and Leyden jar, other and more simple means may be adopted to show the combination of oxygen and hydrogen, and formation of water.

If a little alcohol is placed in a cup and set on fire, whilst an empty cold gas jar is held over the flame, an abundant deposition of moisture takes place from the combustion of the hydrogen of the spirits of wine. Alcohol contains six combining properties of hydrogen, with four of charcoal and two of oxygen. If a lighted candle, or an oil, camphine, Belmontine, or gas flame, is placed under a proper condenser, large quantities of water are obtained by the combustion of these substances (Fig. 119).

Fig. 119.

a. A burning candle, or oil or gas lamp. Copper head and long pipe fitting into b c, the receiver from which the condensed water drops into d. e e. Two corks fitted, between which is folded some wet rag.

Sixteenth Experiment.

During the combustion of a mixture of two volumes of hydrogen with one of oxygen, an enormous amount of heat is produced, which is usefully applied in the arrangement of the oxy-hydrogen blowpipe. The flame of the mixed gases produces little or no light, but when directed on various metals contained in a small hole made in a fire brick, a most intense light is obtained from the combustion of the metals, which is variously coloured, according to the nature of the substances employed. With cast-iron the most vivid scintillations are obtained, particularly if after having fused and boiled the cast-iron with the jet of the two gases, one of them, viz., the hydrogen, is turned off, and the oxygen only directed upon the fused ball of iron, then the carbon of the iron burns with great rapidity, the little globule is enveloped in a shower of sparks, and the whole affords an excellent notion of the principle of Bessemer's patent method of converting cast-iron at once into pure malleable iron, or by stopping short of the full combustion of carbon, into cast-steel.

The apparatus for conducting these experiments is of various kinds, and different jets have been from time to time recommended on account of their alleged safety. It may be asserted that all arrangements proposed for burning any quantity of the mixed gases are extremely dangerous: if an explosion takes place it is almost as destructive as gunpowder, and should no particular damage be done to the room, there is still the risk of the sudden vibration of the air producing permanent deafness. If it is desired to burn the mixed gases, perhaps the safest apparatus is that of Gurney; in this arrangement the mixed gases bubble up through a little reservoir of water, and thus the gas-holder—viz., a bladder, is cut off from the jet when the combustion takes place. (Fig. 120.) This jet is much recommended by Mr. Woodward, the highly respected President of the Islington Literary and Scientific Institution, and may be fitted up to show the phenomena of polarized light, the microscope, and other interesting optical phenomena.

Fig. 120.

Gurney's jet. a. Pipe with stop-cock leading from the gas-holder. b. The little reservoir of water through which the mixed gases bubble. c. The jet where the gases burn. d. Cork, which is blown out if the flame recedes in the pipe, c.

Mr. Woodward states, that a series of experiments, continued during many years, has proved, that while the bladder containing the mixed gases is under pressure, the flame cannot be made to pass the safety chambers, and consequently an explosion is impossible; and even if through extreme carelessness or design, as by the removal of pressure or the contact of a spark with the bladder, an explosion occurs, it can produce no other than the momentary effect of the alarm occasioned by the report; whereas, when the gases are used in separate bags under a pressure of two or three half hundredweights, if the pressure on one of the bags be accidentally removed or suspended, the gas from the other will be forced into it, and if not discovered in time, will occasion an explosion of a very dangerous character; or if through carelessness one of the partially emptied bags should be filled up with the wrong gas, effects of an equally perilous nature would ensue.

Fig. 121.

a. The bladder of mixed gases, pressed by the board, b b, attached by wire supports to another board, c c, which carries the weights, d d. e e. Pipe to which the bladder, a, is screwed, and when a is emptied, it is re-filled from the other bladder, r. f f f. Pipe conveying mixed gases to the lantern, g g, where they are burnt from a Gurney's jet, h.

In the oxy-hydrogen blowpipe usually employed, the gases are kept quite separate, either in gasometers or gas bags, and are conveyed by distinct pipes to a jet of very simple construction, devised by the late Professor Daniell, where they mix in very small volumes, and are burnt at once at the mouth of the jet. (Fig. 122.)

Fig. 122.

Daniell's jet. o o. The stop-cock and pipe conveying oxygen, and fitting inside the larger tube h h, to which is attached a stop-cock, h, connected with the hydrogen receiver. a. The orifice near which the gases mix, and where they are burnt.

The gases are stored either in copper gasometers or in air-tight bags of Macintosh cloth, capable of containing from four to six cubic feet of gas, and provided with pressure boards. The boards are loaded with two or three fifty-six pound weights to force out the gas with sufficient pressure, and of course must be equally weighted; if any change of weight is made, the stop-cocks should be turned off and the light put out, as the most disastrous results have occurred from carelessness in this respect. (Fig. 123.)

Fig. 123.

Fig. 123. Gas bag and pressure boards.

The oxy-hydrogen jet is further varied in construction by receiving the gases from separate reservoirs, and allowing them to mix in the upper part of the jet, which is provided with a safety tube filled with circular pieces of wire gauze. (Fig. 124.) With this arrangement a most intense light is produced, called the Drummond or lime light, and coal gas is now usually substituted for hydrogen.

Fig. 124.

a a. Board to which b b is fixed. o. Oxygen pipe. h. Hydrogen pipe. c c. Space filled with wire gauze. d. Lime cylinder.

Seventeenth Experiment.

There are many circumstances that will cause the union of oxygen and hydrogen, which, if confined by themselves in a glass vessel, may be preserved for any length of time without change; but if some powdered glass, or any other finely-divided substance with sharp points, is introduced into the mixed gases at a temperature not exceeding 660° Fahrenheit, then the gases silently unite and form water.

This curious mode of effecting their combination is shown in a still more interesting manner by perfectly clear platinum foil, which if introduced into the mixed gases gradually begins to glow, and becoming red-hot causes the gases to explode. Or still better, by the method first devised by Dobereiner, in 1824, by which finely prepared spongy platinum—i.e., platinum in a porous state, and exposing a large metallic surface—is almost instantaneously heated red-hot by contact with the mixed gases. When this fact became known, it was further applied to the construction of an instantaneous light, in which hydrogen was made to play upon a little ball of spongy platinum, and immediately kindled. These Dobereiner lamps were possessed by a few of the curious, and would no doubt be extensively used if the discovery of phosphorus had not supplied a cheaper and more convenient fire-giving agent. When the spongy platinum is mixed with some fine pipeclay, and made into little pills, they may (after being slightly warmed) be introduced into a mixture of the two gases, and will silently effect their union. The theory of the combination is somewhat obscure, and perhaps the simplest one is that which supposes the platinum sponge to act as a conductor of electric influences between the two sets of gaseous particles; although, again, it is difficult to reconcile this theory with the fact that powdered glass at 660°, a bad conductor of electricity, should effect the same object. The result appears to be due to some effects of surface by which the gases seem to be condensed and brought into a condition that enables them to abandon their gaseous state and assume that of water.

When Sir H. Davy invented the safety-lamp, he was aware that, in certain explosive conditions of the air in coal mines, the flame of the lamp was extinguished, and in order that the miner should not be left in the dreary darkness and intricacies of the galleries without some means of seeing the way out, he devised an ingenious arrangement with thin platinum wire, which was coiled round the flame of the lamp, and fixed properly, so that it could not be moved from its proper place by any accidental shaking. When the flame of the safety-lamp, having the platinum wire attached, was accidentally extinguished by the explosive atmosphere in which it was burning, the platinum commenced glowing with an intense heat, and continued to emit light as long as it remained in the dangerous part of the mine. Sir H. Davy warned those who might use the platinum to take care that no portion of the thin wire passed outside the wire gauze, for the obvious reason that, if ignited outside the wire gauze protector, it would inflame the fire-damp.

Eighteenth Experiment.

Water is decomposed by passing a current of voltaic electricity through it by means of two platinum plates, which may be connected with a ten-cell Grove's battery. The gases are collected in separate tubes, and the experiment offers one of the most instructive illustrations of the composition of water. (Fig. 125.)

Fig. 125.

p p. Two platinum plates connected with wires to the cups. The wires are passed through holes in the finger-glass, b b, and are fixed perfectly steady by pouring in cement composed of resin and tallow to the line l l. Two glass tubes filled with water acidulated with sulphuric acid, and placed over the platinum plates in finger-glass, which also contains dilute sulphuric acid to improve the conducting power of the water. The wires of the battery are placed in the cups, and the arrows show the direction of the current of electricity.

There is a current of electricity passing from and between two platinum plates decomposing water, offering the converse of the Dobereiner experiment, and highly suggestive of the probability of the theory already advanced in explanation of the singular combination of oxygen and hydrogen in the presence of clean platinum foil, and more especially when we consider the operation of Grove's gas battery, in which a current of electricity is produced by pieces of platinum foil covered with finely-divided platinum, called platinum black; each piece is contained in a separate glass tube filled alternately with oxygen and hydrogen, and by connecting a great number of these tubes a current of electricity is obtained, whilst the oxygen and hydrogen are slowly absorbed and disappear, having combined and formed water, although placed in separate glass tubes. (Fig. 126.)

Fig. 126.

Grove's gas battery consists of tubes containing oxygen and hydrogen alternately, and having a thin piece of platinum foil, p, inserted by the blowpipe in each glass tube. The foil hangs down the full length of the interior of the glass. Each pair of tubes is contained in a little glass tumbler containing some dilute sulphuric acid, and the hydrogen tube, h, of one pair, is connected with the oxygen tube, o, of the next. w w. The terminal wires of the series.

The analysis of water is shown very perfectly on the screen by fitting up some very small tubes and platinum wires in the same manner as shown in fig. 125. The vessel in which the tubes and wires are contained with the dilute sulphuric acid must be small, and arranged so as to pass nicely into the space usually filled by the picture in an ordinary magic lantern, or, still better, in one lighted by the oxy-hydrogen or lime light. If the dilute acid is coloured with a little solution of indigo, the gradual displacement of the fluid by the production of the two gases is very perfectly developed on the screen when the small voltaic battery is attached to the apparatus; and of course a large number of persons may watch the experiment at the same time.

With respect to the application of the light produced from a jet of the mixed gases thrown upon a ball of lime, it may be stated that for many years the dissolving view lanterns and other optical effects have been produced with the assistance of this light; and more lately Major Fitzmaurice has condensed the mixed gases in the old-fashioned oil gas receivers, and projected them on a ball of lime; and it was this light thrown from many similar arrangements that illuminated the British men-of-war when Napoleon III. left her Majesty's yacht at night in the docks at Cherbourg.

Fig. 127.

Cherbourg.

Mr. Sykes Ward, of Leeds, has also proposed a most simple and excellent application of the oxy-hydrogen light for illumination under the surface of water, and for the convenience of divers, who are frequently obliged to cease their operations in consequence of the want of light. Mr. Ward's submarine lamp consists of a series of very strong copper tubes, which are filled with the mixed gases by means of a force-pump; and in order to prevent the lamp being extinguished, it burns under double glass shades, which are desirable in order to prevent the glass immediately next to the light cracking by contact with the cold water.

Fig. 128.

a a. Tube reservoir to hold the mixed gases. b. The jet and lime ball. d. The first glass shade, held down by a cap and screw. c. The second glass shade. e e. The handle by which it is lowered into the water.

The author tried this lamp at Ryde, and although the coast-guards objected to the production of a brilliant light at night, which they stated might be mistaken for a signal and would cause some confusion amongst the war vessels in the immediate neighbourhood, enough experiments were made, to show that the Ward lamp would burn for a considerable time under water, and could be kept charged with the gas by means of a process that was easily workable in the boat. The gases were taken out mixed in gas bags, and pumped into the reservoir when required. With a much larger reservoir greater results could be obtained; and if nautilus diving bells are to be used in modern warfare, they will require a powerful light to show them their prey, so that they may attach the explosives which are to blow great holes in the men-of-war.

Fig. 129.

Submarine lamp.