The Mastery of the Air

the curious experiment of filling paper bags with smoke, and letting them rise up towards the ceiling. These young me

. "Why does smoke rise?" they asked. "Is there not some strange power in the atmosphere which makes the smoke from chimneys and e

estions were in the mind of James Watt when he was discovering the power of steam. But one of the most im

ng serious was wrong, stayed to watch the tiny balloons rise a little way from the thin tray which contained the fire that made the smoke with which the bags were filled. The experiments were not altogether successful, however, for the bags rarely rose more than a foot or so from the tray. The neighbour suggested that they should fast

n the eve of some great discovery, and, as events proved, they were not far wrong. For a time they imagined that the fire they had used generated some sp

l gas being used, but owing to the expansion of air under the influence of heat, whereby hot air tends to rise. Every schoolboy above the age of twelve k

ade a fire similar to that used in their first experiments, and succeeded in making the bag

66 Cavendish proved conclusively that hydrogen gas was not more than one-seventh the weight of ordinary air. It at once occurred to Dr. Black, of Glasgow, that if a thi

iberius Cavallo, an Italian chemist, succeeded in making, with hydrogen gas, soap-bubbles which rose in the air. Previous

er on, the newly-discovered hydrogen gas; but with both these agents they were unsuccessful. It can easily be seen why steam was of no use, when we con

erical vessel used in chemistry, which was known by that name. To the brothers Montgolfier belongs the honour

n, over 30 feet in diameter. This was accomplished over a fire made of wool and straw. The ascent was suc

in order that the citizens of the metropolis should have their imaginations excited by seeing the hero of these remarkable experiments. Montgolfier was not a rich man, and to enable him to continue his expe

ould be the fate of the "poor creatures". Some people imagined that there was little or no air in those higher regions and that the animals would choke; others said they would be frozen

renchman, from King Louis down to his humblest subject. Strange, was it not, though scores of millions of people had seen smoke

n rising to the required height. But the difficulty was to reach the surface of this aerial sea. To do this he proposed to make a large hollow globe of metal, wrought as thin as the skill of man could make it, so that it might be as light as possible, and this vast globe was to be filled with "liquid fire". Just what "liquid fire" was, one cannot attempt to explain, and it is doubtful if Bacon himself had any clear idea. But he doubt