The Boy's Playbook of Science Part 13

The bill distributor consists of a long piece of wood, to which are [Page 117] attached a number of hollow fuses, with packets of bills, protected from being burned or singed by a thin tin plate; 10,000 or 20,000 bills can thus be delivered, and the wind a.s.sists in scattering them, whilst the balloon travels over a distance of many miles. It must be recollected that in each case the sh.e.l.ls and the bills are detached by the string burning away as the fire creeps up from the fuse. (Fig.

116.)

Another most ingenious arrangement, also prepared by Mr. Darby, is termed by the inventor, the "Land and Water Signal," and may be thus described:--A short hollow ball of gutta-percha, or other convenient material, five or six inches in diameter, and filled with printed bills, or the information, whatever it may be, that is required to be sent, is attached to a cap to which a red flag, having the words "_Open the sh.e.l.l_" and four cross sticks, canes, or whalebones with bits of cork at equal distances, are fitted. The whole is connected by a string to the fuse as before described. These signals are adapted for land and water: in either case they fall upright, and in consequence of the sticks projecting out they float well in the water, and can be seen by a telescope at a distance of three miles. (Fig. 117.) Many of these signals were sent away by Mr. Darby from Vauxhall; one was picked up at Harwich, another at Brighton, a third at Croydon; in the latter case it was found by a cottager, who, fearing gunpowder and combustibles, did not examine the sh.e.l.l, but having mentioned the circ.u.mstance to a gentleman living near him, they agreed to cut it open; and intelligence of their arrival, in this and the other cases, was politely forwarded to Mr. Darby at Vauxhall Gardens.

[Ill.u.s.tration: Fig. 117. The land and water signal, which remains upright on land, or floats on the surface of water. A. The water-tight gutta-percha sh.e.l.l, containing the message or information. B B B. Sticks of cane to keep the flag in an upright position; at the ends are attached cork bungs.]

Balloons, like a great many other clever inventions, have been despised by military men as new-fangled expedients, toys, which may do very well to please the gaping public, but are and must be useless in the field.

Over and over again it has been suggested that a balloon corps for observation should be attached to the British army, but the scheme has [Page 118] been rejected, although the expense of a few yards of silk and the generation of hydrogen gas would be a mere bagatelle as compared with the transport and use of a single 32-pounder cannon. The antiquated notions of octogenarian generals have, however, received a great shock in the fact that the Emperor Napoleon III. was enabled, by the a.s.sistance of a captive balloon, to watch the movements and dispositions of the Austrian troops; and with the aid of the information so obtained, he made his preparations, and was rewarded by the victory of Solferino; and as soon as the battle was over Napoleon III. occupied at Cavriana the very room and ate the dinner prepared for his adversary, the Emperor Francis Joseph.

Over and over again the most excellent histories have been written of aerostation, but they all tend to one truth, and that is, the great danger and risk of such excursions; and to enable our readers to form their own judgment, a chronological list of some of the most celebrated aeronauts, &c., is appended.

1675. Bernair attempted to fly--_killed_.

1678. Besnier attempted to fly.

1772. L'Abbe Desforges announced an aerial chariot.

1783. Montgolfier constructed the first air balloon.

" Roberts _freres_, first gas balloon, destroyed by the peasantry of Geneva, who imagined it to be an evil spirit or the moon.

1784. Madame Thible, the first lady who was ever up in the clouds; she ascended 13,500 feet.

" Duke de Chartres, afterwards _Egalite_ 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 s.h.i.+p 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 n.o.bleman 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_. [Page 119]

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. c.o.c.king--parachute from gas balloon--_killed_.

1847. G.o.dard--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.

[Ill.u.s.tration: Fig. 118. Flying machine (_theoretical_).]

[Page 120]

_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 gla.s.s.

_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 gla.s.s tubes of various sizes, the most peculiar sounds are obtained. The hydrogen flame should be extremely small, and the gla.s.s 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 [Page 121] 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 gla.s.s 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-c.o.c.ks, 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 quant.i.ties of water are obtained by the combustion of these substances.

(Fig. 119.)

[Ill.u.s.tration: 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.]

[Page 122]

_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 a.s.serted that all arrangements proposed for burning any quant.i.ty 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 Inst.i.tution, and may be fitted up to show the phenomena of polarized light, the microscope, and other interesting optical phenomena.