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[[start page]] [[left-hand column]] 338 THE MIRROR. THE NEW GREAT MONTGOLFIER BALLOON. EVERY one at all acquainted with the history of Aeronautics must remember the well-earned celebrity of the Montgolfiers, about half a century since. Balloons constructed upon the principle first experimented by these ingenious persons, are called Montgolfiers from the toy balloon which we are accustomed to start for the delight of our family at home to the stupendous machine destined to amuse many thousands of "children of a larger growth." The Montgolfiers may, however, be more properly called "Smoke Balloons;" for they are filled with white smoke, found by computation to be, at least, one third specifically lighter than the common air. This purer sort of smoke is scarcely any thing but air itself charged with vapour, being produced, (by the inventors) by the burning of chopped straw or vine twigs, in a brazier, under the orifice of the bag. It would have required no fewer than 150 degrees of heat alone to cause the same extent of rarefaction. As this process is carried on while the balloon is in the air, its management must require the most careful superitendence; since the proximity of a lighted furnace to many hundred yards of varnished linen, the escape of sparks, &c., are somewhat fearful to contemplate. In the fabrication of the Montgolfier about to be described, the above point has been strictly attended to; and, in the construction of the furnace lies the main improvement upon the inventor's original plan. The practicability of the ascent has likewise been tested by experiments already made in Essex; so that there is nothing to cause apprehension from inexperience on the part of the aeronauts or manipulators. We have often had occasion to notice novelties in nature, science, or art, as first introduced to the public at "the Surrey Zoological Gardens;" but never one more extraordinary than the immense aerostatic machine bearing the above cognomen, which is to make its first ascent from these excellently adapted grounds on Thursday next. Since the first discovery of balloons by Stephen and Joseph Montgolfier in 1782, there has not been an ascent of so extraordinary a nature, or which has excited so intense and general an interest. It is the first that has ever taken place in England with an aerostat on this beautifully simple, but seldom used plan. The balloon has been constructed by a party of gentlemen, interested in the art of aerostation; and its fabrication has occupied many months of uninterrupted labour, during some period of which upwards of 100 women have been engaged in sewing the seams of the vast machine together. The New Montgolfier is the largest and most powerful aerial machine ever built in [[continued right-hand column]] this country, being 130 feet from the bottom of the car to the upper rim of the balloon, and 200 feet at its greatest circumference. It is, therefore, the height of the York Column; and its circumference is nearly half that of the dome of St. Paul's Cathedral. It contains, when fully inflated, 170,000 cubic feet of air. The car is fifteen feet by eight, gorgeously ornamented, and made of cane: it has an aperture in the bottom, through which part of the furnace drops. The furnace is of very ingenious and peculiar construction. The chimney from it is placed in the lower aperture of the balloon, while the aeronauts are able, with the most perfect convenience, to regulate the quantity of fuel. The degree of heat can be raised to 200 of Fahrenheit in three minutes, and depressed to that of the surrounding atmosphere almost as quickly; and the balloon can be fully inflated by the great power of this furnace in eight minutes. When in that state it presents the peculiar egg shape represented in our Engraving, being cut off quite abruptly at the bottom, and there leaving an aperture of 46 feet in circumference. This is formed of rope bound with basil, and lies as flat as any other part of the machine, until the inflation takes place. To this another very strong hoop, formed of ash, bound with cane, is suspended, and on it depends the weight of the car and its appurtenances. There is no net-work, as in the gas balloons; but its absence is supplied by a line being sewn down each of the 58 gores with the material, and terminating in the neck-rope before described. The grapnel is the invention of the constructor of the balloon, and is very powerful: it weighs 85 lbs., and is so made, that in case of any single fluke, of which there are six, being broken off, it can be easily replaced by means of a nut and screw. Having a swivel head, there is also less danger of breaking the cable attached to it. The fuel consists of small bundles of wood prepared in a particular manner, chopped straw, and willow rinds; many hundred pounds of which materials will be taken up. The machine has an ascending power equal to the weight of fifteen or twenty persons. The fabric is lawn, covered with a peculiar varnish, and thus made impermeable. It is extremely light. The apparatus for inflating it is very extensive; a large platform being raised about twelve feet above the Lake in the Gardens, with an aperture from which the heated air ascends into the balloon. It is necessary to elevate the crown of the balloon to about half its height before the inflation is commenced; and for this purpose two, large, stout spars, of about ninety feet in height, will be raised; and by means of a rope passing through blocks, the machine will be hauled up, until it gains sufficient ascensive power to sustain its own weight. Of the ascent we hope to present satisfactory details in our ensuing Number. [[end page]] [[start page]] 42 THE PENNY MECHANIC. [[left-hand column]] THE GREAT MONTGOLFIER; OR, FIRE BALLOON. Nearly two-thirds the height of the Monument, and containing, when inflated, 170,000 cubic feet of air. THE scheme of the Montgolfier is again to be put to the test on Thursday next, the birthday of her Majesty, at the Surry Zoological Gardens, when several gentlemen, (who have for a long time been engaged in the construction of an immense balloon, measuring 130 feet in height, and 200 feet in circumference) will make their ascent. Its ascending power is calculated at 2,400lbs., and it would consequently carry up from fifteen to twenty persons. Its fabric is a peculiar kind of lawn, prepared with a sort of varnish, which combines extreme lightness with great durability and strength. The car is fifteen feet long, and eight feet wide, and is made of wicker work, ornamented most gorgeously. The necessity for netting is obviated by an ingenious plan of fastening a line down each gore or seam, the whole of the seams terminating in a stout hoop made of several thicknesses of cane bound together, and forming an aperture of forty-six feet in circumference. Another striking peculiarity is the close approximation of the car to the aperture or neck of the balloon, and the consequent shortness of the suspending cords. This is done for the purpose of introducing the furnace-chimney into the neck of the balloon, at the same time that the aeronauts in the car have a perfect command over the radiation of heat, which can be raised or depressed in an incredible short space of time. The chief improvement on the original machines of Montgolfier, is in the construction of the furnace. The first aeronauts, as Pilati, Rozier, and others, who ascended in France, used merely an open brazier, which was of course attended with great danger; but by this invention that danger is entirely avoided; for although the air can be rarefied to 200 degrees, no fire or sparks ascend into, or can come in contact with the balloon. The fuel with which the furnace is supplied, consists of straw, wool, and small faggots of brushwood, prepared in a particular manner. The grapnel is a very powerful instrument, and is also of peculiar construction. It weighs eighty-five pounds. Although this kind of aerostat appears at first sight to labour under many disadvantages, it will be found, upon consideration, that there are facilities which render it equal, or in some respects superior, to a gas-balloon. For instance, there is no danger, as in the case with the latter, of bursting the machine, by the sudden rare- [[continued right-hand column]] faction of the gas, by the sun's rays, when rising suddenly above a cloud, or throwing out a large quantity of ballast at one time; because it would be impossible to heat the air contained in the balloon by the action of the rays of the sun, to a greater degree than is done by the fire in the car, before the ascending power is gained. The descent is also expected to be much more easy than with a common balloon, on account of the great size of the aperture at the bottom, discharging all its contents almost immediately. A contemporary journal, says "It is surprising that no one has thought of returning to the original plan of filling with heated air. The idea, however, does not seem to have struck any one until last autumn, when a number of scientific gentlemen determined to try what could be done in the way of improving the construction of the balloon, as first invented by the brothers, Montgolfier, in the year 1782." By referring, however, to Number 32, of our Magazine, for June 1837, we find the following account of an ascent in a Montgolfier. "Novel Ascent in a Fire Balloon.- A young gentleman, of the name of Sneath, residing at Mansfield, has made a large fire balloon of fire-proof canvass. On Wednesday evening he was anxious to try its buoyancy, and, inflating it, took it at nine o'clock to the Bleak-hill, where he thought he had secured it to the earth. He got into the car to see what weight it would carry, when the sudden bounds given by the machine disengaged the cords, and he rose in the air. He remained in the balloon, floating about, until eleven o'clock, when the machine began to descend, and the grapnell caught in a hedge near Spondon. Here, however, another difficulty presented itself: if he got out of the car the balloon would rise, so he determined to keep his seat until the next morning, when, to his great joy, he received the assistance of some countrymen, about half-past four, when he packed up his ponderous machine and conveyed it to the nearest town (Derby)." Monday, May 20. The Oriental Diamond.- We find by Ritter, that it is found over a large extent of the borders of the table land of the Deccan, from the 14th to the 25th degree of latitude. It is there seen in a loose, conglomerated sandstone, of but a few feet, and more or less deep beneath the surface. Gold is also found there occasionally. The conglomerate consists of quartz, ironstone, jaspar, chalcedony, cornelian, and brown iron-ore. [[end page]]
