Hot Air Balloons

Hot Air Balloons were invented before the 19th century. In fact the first recorded launch was in 1783. However a lot of history was covered during the 19th century with regard to improvements and air travel. With that in mind, I've selected a tidbit from "The Literary Digest" ©1898. On a completely different note, take note of the lack of punctuation at the end of each paragraph. This publication was produced by Funk & Wagnalls Company in NY.

IMPROVEMENTS IN BALLOONS.

WHILE hosts of inventors are trying to make a flying-machine that will travel through the air without the aid of the ascensional force of a rarefied medium, others are experimenting to see whether the old-fashioned balloon is not susceptible of improvement. Some of the plans proposed for making ascensions cheaper and giving the balloonist better control of his craft are mentioned in an article contributed to the Revue Scitntifique (Paris, September 10) by M. H. de Graffigny. Says this writer:
"The greatest part of the expense of a free ascension is due to the high price of the gas used for inflation, whose density is also quite great. The Paris company charges aeronauts ao centimes a cubic meter [about 4 cents a cubic yard] for gas from its works at La Villette, and this gas has an ascensive force of not more than 700 grams to the meter [i^ pounds to the cubic yard], under the most favorable conditions. It has been*impossible, up to the present time, to get any improvement in these conditions, . . . and the result is that balloon trips are necessarily few

"Some investigators, finding hydrogen too costly, are talking of a return to the old Montgolfier balloon, filled only with rarefied air or with water vapor at high pressure. These methods have the advantage of being very economical, and we even have reason to ask why they were ever abandoned. Information on this subject is not easily to be found, and to form an opinion we have been obliged to question specialists and repeat several experiments to base theory and calculation on reality."

M. Regnault thus finds that the old hot-air balloons were very economical, that they were inflated more rapidly than the gas balloon, and that some of the most remarkable ascensions in the history of ballooning were made with them; but that they were forbidden by police-regulation in 1785 on account of the danger from fire, and that more recent experiments with them have not been successful, altho methods have been devised by several inventors for keeping the air hot within the balloon without running much risk of setting fire to it. After a mathematical calculation, the author concludes that a long trip in a hot-air balloon is impossible unless some method be devised for preventing the enormous loss of heat that at present takes place by radiation from the surface of the envelope. The hot-air balloon costs only about one third as much as the gas-balloon and can be made much lighter, but it offers a larger surface to the wind, and is more susceptible to atmospheric conditions, without speaking of the dpnger of firewhich never can be entirely eliminated. This danger, which always attends the hot-air balloon, has suggested the so-called "thermosphere" of M. Emmanuel Aim6, which is described by its inventor in the following terms:
"The thermosphere is nothing else than a balloon partially filled with gas and heated by steam.

"Suppose an impermeable envelope into which is introduced a quantity of gas whose ascensional force is insufficient to raise the balloon with its contents, even on the supposition of a maximum dilatation under the influence of the most intense solar radiation. In the basket is placed a Serpollet steam-generator, heated by a petroleum burrer, whose flame is enclosed, like that of a miner's lamp, in metal gauze, to avoid all risk of fire.

"The steam is conducted into the interior of the thermosphere by a tube with an automatic valve. It produces a double effect: it dilates the gas by its heat and it increases its volume by becoming itself part of the mixture.

"When the quantity of steam thus introduced is sufficient to saturate the gas it condenses on the interior surface and the water runs back through a tube into the reservoir. . . . Thus, as liquid and vapor alternately, the water passes around a closed cyclecarrying heat to the gas and thus converting into mechanical work the energy set free by the combustion of the petroleum

"To start the balloon, we have only to introduce steam, and to descend, we have only to shut it off. In no case is the aeronaut at the mercy of his gas, as in an ordinary balloon, since the gas alone is unable to lift him without the aid of the steam. It is thus possible to travel at any height between the level of the earth's surface and a superior limit which is about 6,000 feet, and that, too, without losing gas. . . . The equilibrium depends only on the turn of a valve; when the sun is shining the steam is turned off a little; when it goes under a cloud the steam is turned on again

"To sum up, the use of steam to give ascending force and as a regulator of equilibrium enables the aeronaut to rise and descend at his will. He can choose and maintain a given altitude, without other loss than that of his fuel, of which he can obtain a fresh supply by descending to the ground. Provided he keeps over inhabited regions, he may take indefinitely long trips. Finally, he may hope to direct his craft by rising or falling till he finds himself in a favorable air-current."

Of these claims, M. de Graffigny speaks, in closing, as follows:
"We shall say nothing further of this plan, for the near future will show whether its claims are just or unfounded, but our conclusion is that there still remains much to do before we shall obtain the ideal balloon that inventors dream of. Nevertheless, many minds are working on this difficult problem, improvements in detail will be worked out little by little, and we do not doubt that in the next century aerostation will be a mode of locomotion, or at least as popular a sport as automobilism is at present."— Translated Jor The Literary Digest.