AERIAL EXCURSION OF MA

DAMOISELLE GARNERIN. THE number of ascents recently made in balloons attracting at present some attention to this subject, we purpose to give a very short account of the principles on which Balloons rise in the air, and of the more hazardous and dangerous experiment of descending from them, wlien at a great height, by means of parachutes. The insatiate ambition and inexhaustible ingenuity of man have led him in all ages eagerly to imitate whatever he thought would add to his power. Not content with the enjoyments of the land, he has long, in imitation of the funny tribes,

taken up his abode on the waters, and cleaving through them, with the swiftness of the most rapidlymoving fish, has obtained, by means of another element, the air, a dominion over the ocean. He would fain also fly like the birds, and has for many ages tasked his ingenuity to make wings for him. self. As he cannot travel far on the water, but by the help of ponderous machines, being incapable, from the structure of his body, to live, and breathe, and float, in that liquid element, like its native inhabitants; so neither can he fly in the air after the manner of birds. It has been satisfactorily demonstra ed by anatomists, that the pectoral D

in the

muscles, or those which move the arm backwards and downwards,are so weak in the human frame, in proportion to its weight, compared with the same organs feathered tribes, that man, however ingeniously he may adapt wings to his body, never can sustain himself for any length of time, by their means alone, above the surface of the earth. A balloon, however, is to the air what a ship is to water; it enables man to rise even beyond the most adventurous of the feathered tribes. The poets, indeed, feign that the eagle soars to the sun, but the philosopher knows that the tenacity of the atmosphere and the cold of the upper regions, do not allow him to live so high as the very summit of our highest mountains, or even to reach them. Mr. Gay Lussac, a French chemist of great celebrity, ascending from Paris on the 15th of September, 1804, for the purpose of making experiments in the upper regions of the air, rose to the prodigious height of 23,040 feet, or more than four miles and a quarter above the level of the sea, which is considerably higher than the highest mountains. of our globe. Thus can the mind of man conquer even the physical difficulties opposed by the structure of his body to his ambition; and even surpass in their own element, both fishes and birds. We are indebted, it is said, to Albert, an Augustin monk of Saxony-the same order to which Luther afterwards belonged, and who lived in he fourteenth century, for the first dea of our present balloons. He observed, that fire was lighter than air, and that, inclosed in a hollow globe, it will make it rise and keep it suspended above the earth. The first balloon was constructed on this principle and after this manner, though it is probable that the remark of the Saxon monk had never reached the ears of the enlightened and ingenious paper manufacturers, Stephen and Joseph Montgolfier, who first, on June 5th, 1783, actually sent up a messenger to prepare, we had almost said the

skies, but the higher regions of the air, to submit to the dominion of man. Their balloon was merely a bag made of linen, and filled by kindling under it, and keeping burning for some time a fire made of chopped straw. It was launched from Annonay, a little town on the banks of the Rhone, about forty miles below Lyons. On Nov. 21st of the same year, a young man, by the name of Pilatre de Rozier, who two years afterwards attempting to cross the channel from Boulogne, lost his life, by the balloon catching fire, was the first person who ever ascended in a car attached to a balloon. He and Montgolfier adhered to their plan of filling the balloon with heated common air or smoke, which, being much lighter than the atmosphere at the ordinary temperature, carried the bag in which it was inclosed to a considerable height. The progress, however, which chemistry was making about that period soon led to other means of filling balloons, which, if not so cheap, are more elegant and manageable. It had been discovered, not many years before, that there were different species of air or gases, differing very much from each other in their elasticity and weight. One of the lightest of these, hydrogen gas, is six times lighter than common air. few weeks after the first experiment of Montgolfier, Messieur Charles and Robert constructed balloon at Paris, which was filled with this gas. They neglected, however, to purify the gas, and it injured the silk so much that the experiment failed. Means were soon fallen on to get over this difficulty, and balloons filled with purified hydrogen gas were employed. At present the material generally employed to construct balloons is thin silk. Lately Mr, Graham, we are informed, has substituted a species of gause, which is equally light and less expensive Whatever material may be employed, it is necessary to make the whole air-tight, and to effect this, a varnish, made of elastio

A

gum or india rubber, and spirits of turpentine, is generally employed. The hydrogen gas is produced by the decomposition of water, of which it is a constituent element. On the present occasion we cannot enter into an elaborate explanation of the manner of obtaining this air. It may be enough shortly to observe, that iron, or zinc, when in a heated state, readily decomposes water if brought into contact with it in the state of steam. The iron takes the oxygen of the water, setting the hydrogen gas at liberty, which is purified by passing it over caustic lye, before it is transmitted into the balloon. Or diluted sulphuric acid is poured on the filings of iron or zinc, which enables the metal to decompose the water, and set at liberty the hydrogen it contains. Hydrogen, though not in so pure a state, may also be obtained by subjecting coal and various other substances to the action of a red heat while they are excluded from the atmosphere. On this principle the gas with which our streets is lighted up is procured; and thus by the same instrument we are enabled both to mount into the air and to illuminate darkness.

The most extraordinary, because the latest invented, and the most dangerous experiment with balloons, is that of descending from them by means of the parachute, or fall preventer. M. Blanchard, long celebrated as an aeronaut, and who actually in company with Dr. Jeffries, an American gentleman, crossed the British channel from Dover to Calais, in January 1785, was the inventor of the Parachute. In 1785, this adventurous traveller in an aerial journey which he made of more than 300 miles, sent down a parachute, having a basket in which was a little dog, appended to it; the poor animal falling gently through the air, reached the ground in safety. This instruIment is of the form of a large umbrella, but during the ascent of the balloon, it hangs down like a curtain. It is attached to the net which covers

the balloon, and bears suspended to its outer rim a wicker basket." The traveller seats himself in this basket, and at his own pleasure cuts the cords by which the parachute is fixed to the balloon; he immediately falls with great rapidity; as the parachute expands, the velocity is checked; till, at length, an equable and regular motion succeeds, and the adventurer gradually reaches the earth. The first person who ever used a parachute in this country was. M. Garnerin, who, on September 8, 1802, ascended from an inclosure near North Audley-street. At a vast height he cut the cord; the parachute passed over Mary-le-bone, and Somers town, and alighted in a field near Pancras. One of the stays or pieces of tape which serve to expand the canvass, unfortunately gave way, and disturbing the balance of the machine, threatened the adventurer with destruction during the whole of his descent. On reaching the ground the shock was very violent, and M. Garnerin received some severe injuries. The same spirited æronaut subsequently made repeated descents, and all of them have been successful. Ashe advanced in life, his daughter, who may well be called the heroine of parachutes, succeeded him in his adventurous undertakings, and has made several descents in the parachute with never-failing success. Other ladies have not been sc fortunate, and Madame Blanchard, in 1820, met with an untimely fate at Paris. The parachute struck against a tree, she was precipitated to the earth, and dashed to pieces. Her fate seems to have had no influence on Miss Garnerin, who recently ascended from the Champ de Mars near Paris, and descended unhurt. [See Prefixed Engraving] Of this flight we have seen nothing but a general account, and shall therefore close our article with a

From some misconception of our in. structions, the figure of the parachute in the prefixed engraving is incorrect. The basket should have been represented suspended by ccrds from the different points of the outer rim of the umbrella,

short notice of her excursion from the same spot on Sunday, April 28th, 1816, which we had ourselves the pleasure of witnessing. The weather was favourable, being fine with a light steady breeze; and Paris had sent forth all its chivalry to witness the shew. The sun shone, and the countenances of the people, ever dressed in fashionable smiles, gave a cheerful hilarity to the scene. The hour fixed for the ascent was three o'clock, but, as is usual on such occasions, it was two hours later before every thing was prepared. Then the loud-mouthed gun told the event to all Paris, and the balloon, with Miss Garnerin hanging beneath it waving her flags as an eagle flutters his wings, rose majestically upwards. Miss Garnerin was calm and unruffled. After rising slowly, and taking a north-easterly direction across the Seine, for about 20 minutes, when she had reached the elevation or nearly half a mile, another gun was fired, and the intrepid heroine cut the cord, and hastened back to her mother earth. Continuing its north-east direction, the parachute passed over the villages of Chaillot and Passey, and descended with the lady unhurt in the wood of Boulogne. Numbers of people who had followed with as much haste as possible on horseback, in carriages, and on foot, soon surrounded her; she was extricated without any difficulty from her aerial car, mounted on a horse, attended by all the cavaliers who could get near her, and cons ducted in glad triumph back to Paris.

SPEAKING AUTOMATON.

M. Piquet [Qu. Pictet?] of Geneva, another Vaucanson, has constructed a mechanical wonder, which he exhibits at Paris. It is a sorcerer, capable of answering with an astonishing precision every question, however difficult, that the company may choose to demand. Crowds have already begun to consult this oracle, at least equally wise and equally inspired with those of antiquity, before which the wise Greeks and the mighty Romans prostrated their bodies and their intellects.(Literary Gazette.)

MR. PERKINS'S NEW STEAM

ENGINE.

It is a circumstance generally known that water may be raised to any tenrpe. rature, provided it be prevented from passing off in vapour; that, in fact, by keeping it subjected to a certain pressure; it may be made red hot. On this depends the important discovery of Mr. Perkins. In place of the boiler in the ordinary Steam Engine, Mr. Perkins employs a generator, consisting of a cylinder of gun-metal, which is more tenacious, and less liable to oxidation than any other. It is three inches thick, contains eight gallons of water, and is closed at both ends, with the exception of five openings for tubes. It is placed vertically in a cylindrical furnace, in which, by the aid of bellows, it is kept at a temperature of from 400 to 450, the water being brought up to the same heat. The valves in the tubes that convey the steam are loaded, one with 35, the other with 37 atmospheres, so that none of the fluid can escape till the heat creates a greater force. By means of a compressing pump, the handle of which is wrought by the engine, water is forced into the generator, the valve loaded with 35 atmospheres is opened, and a portion of the hot and compressed fluid flashes out in the form of steam of high elasticity, and of a temperature 420, and is conveyed to a horizontal cylinder containing the piston, to which it communicates motion. Having performed its office, it is carried into a condenser, where it is converted into water, at a temperature of about 320, and under a pressure of five atmospheres, whence it is drawn into the forcing pump, again to be thrown into the generator. The pump acts with a pressure of 35 atmospheres; consequently when the water is urged from it into the generator, it must expel a portion equal to itself in volume, which, as already mentioned, the moment it escapes, is converted into steam of high elasticity; and as the pump is so contrived as to act with a steady force, the water must escape in a continuous stream; there is thus a constant supply to produce the moving power, the motion, of course, being occasioned by the difference in the elasticity of the steam on the opposite sides of the piston, that introduced from the generator acting with a force of 35 atmospheres, or about 500 lb. on the square inch that connected with the condenser acting

with a pressure of five atmospheres, or about 70 lb -the difference 430 being the power gained. When there is a surplus of water in the generator, occasioned by working the pump too violently, or by the heat becoming too high, part of it escapes through the valve loaded with 37 atmospheres, and is conveyed into the condenser.

From the high elasticity of the steam, It has been supposed that this engine is very liable to be burst: this is, however, a mistake; for as the steam is only generated in sufficient quantity to produce each succeeding stroke of the piston, there is no collection of it, as in the common high-pressure engines, exposing a large surface to its expansive force, so that the ordinary source of danger is avoided.

But in order to remove all apprehensions, the pipe coming from the generator, and in which the steam is formed, is made so strong, as to sustain an internal pressure of four thousand pounds, which is eight times more powerful than the force with which the engine works. This enormous superabundance of strength is still further. secured by means of a safety pipe proceeding from the generator, and provided with a copper bulb, made so as to burst at a pressure of a thousand pounds on the square inch; and owing to the nature of this metal, it merely tears like a piece of paper, so that when it does burst, as Mr. Perkins has made it frequently do, it occasions no injury whatever, either to spectators, or to the apparatus. This safety tube is also made to communicate with an indicator, having a dial plate and index, by which the force of the steam is ascertained.

The engine we have now described is at present at work in Mr. Perkins's manufactory. It is calculated as equal to a ten-horse power. The cylinder is only two inches in diameter, and 18 long, with a stroke of twelve inches, and when in full power it consumes only two bushels of coals in a day.

The space occupied by it is only six feet by eight; but Mr. Perkins considers, that with the exception of the piston and cylinder, the apparatus is sufficient for a 30-horse power engine. Its operations have been witnessed, and minutely examined by philosophers and engineers; and the most unreasonable sceptics have been compelled to acknowledge the justness of its principles, as well as the energy of its operations. Mr. Perkins has not, however, been

content with this. He has discovered a mode of conveying the benefit of his original principle to steam engines of the old construction, which, when we consider the enormous capital already vested in steam-engines, and the skill and elegance with which they perform their functions, must be considered equal in value to his original discovery. For this the old engines with their boilers are retained unaltered; the furnaces alone are removed. A generator is constructed consisting of three horizontal tubes of gun-metal connected together,, filled with water, and supplied with fluid from a forcing pump, as in his own engine. This is exposed to heat in the same manner; so that by means of a loaded valve, the hot fluid may be constrained till forced out of it into the water in the old boiler, and thus as much low-pressure of four pounds on the square inch may be generated by one bushel of coals, as could be produced in the old engine by nine.

Mr. Perkins has lately made another discovery, which promises to be of great practical importance. He now dispenses with the condenser, and works the engine against the atmosphere alone; and by a method which he has not yet thought it prudent to disclose, he is enabled to arrest the heat after it has performed its mechanical functions, and actually pump it back to the generator, to unite with a fresh portion of water, and renew its useful labours.

METHOD OF PREPARING CHARCOAL AND
RED & BLACK CHALKS FOR DRAWING.
INVENTED BY MR. PYE.
[From Transactions of the Society of Arts,]

The finest grained charcoal that can be procured is sawed into slips of the size and form required and put into a pipkin of melted bees'-wax, where they are permitted to remain near a slow fire for half, an hour or more, in proportion to the thickness of the charcoal: they are then taken out, and, when perfectly cool, are fit for use. By adding a small quantity of rosin to the wax, they may be made considerably harder; and on the contrary, should they be required softer, a little butter or tallow will answer the purpose. The advantages these pencils possess are, that they can be made at the most trifling expense, and at any time; and that draw. ings made with them are as permanent as ink, and not liable to injury by being rub bed, or remaining in the damp.