But they were immediately confronted with a difficulty. Hydrogen being the lightest and most subtle of gases, they were at a loss to know of what material to make their balloon, to prevent the gas escaping. After several failures they eventually constructed a bag of a special kind of silk, and coated it all over with a varnish made of indiarubber dissolved in turpentine. As they found great difficulty in manufacturing large quantities of hydrogen, they were forced to make their bag a comparatively small one, about thirteen feet in diameter. On the 25th of August 1783 the bag was successfully filled, and the ascent was made in Paris in the presence of an enormous crowd. The little balloon rose upwards with immense rapidity, until it was lost to sight in the clouds. Ascending yet higher, it presently burst, and came to the earth in a village, fifteen miles away, after a voyage of three-quarters of an hour. [Illustration: ATTACK ON THE FIRST CHARLIER BALLOON.] In the field where the balloon fell a party of peasants were at work; at its approach they fled in abject terror. From a safe distance they watched the strange new monster settle to earth and lie prone, and then they cautiously drew nearer to inspect it. The silk still heaved with the escaping gas, and the countrymen were fully convinced that an actual living creature of mysterious nature lay before them. One man seized his gun and fired full at it, and then supposing it to be mortally wounded, they all rushed in with flails and pitchforks to complete its destruction, finally tying it to the tail of a horse, who galloped with it all over the country, tearing it to shreds. It was small wonder that after such an occurrence the French Government issued a proclamation to the people, telling them that these aeronautical experiments were to be repeated, and warning them not to be alarmed if they saw a balloon in the air, since it was a perfectly harmless machine filled with gas, and incapable of injuring any one. This event took place about three months after the first public ascent of the hot-air balloon. The new craft was immediately called a “Charlier,” after its inventor, and to distinguish it from the “Montgolfier.” There followed various exhibitions of the rival airships, and after the voyage of Pilâtre de Rozier and the Marquis D’Arlandes, Messrs. Charles and Roberts resolved also to hazard an ascent in a balloon inflated with hydrogen.