io8 OUR PHYSICAL WORLD 



below by telephone, the wire of which runs down the cable by 

 means of which the balloon is held. This cable winds on to a 

 drum that is revolved by a small engine so the balloon may be 

 brought down quickly if desired. 



In all of the early balloon ascensions the balloonist was at the 

 mercy of the winds, but early in the history of the balloon 

 attempts were made to propel it. It was early suggested that 

 a balloon might be equipped with sails and a rudder, as is a ship, 

 but, of course, it was found that such a balloon, because it offered 

 so large a surface to the wind, still drifted before the wind and 

 could not get headway enough to steer. A French general by 

 the name of Meusnier had a balloon made equipped with large 

 cloth-covered oars and a rudder. The oars were torn away on 

 the experimental flight by the winds, and the experiment was a 

 failure as far as controlling the balloon was concerned. 

 Meusnier's balloon, however, was an improvement in one 

 respect it was a long, cigar-shaped affair so built as to offer less 

 resistance to the air. He suggested another improvement. One 

 of the difficulties in the early balloons was that the gas would 

 escape and the balloon would become shrunken and out of shape. 

 He proposed putting a bag into the balloon which might be 

 pumped full of air as the gas escaped and so maintain the shape. 

 Another Frenchman by the name of Giffard was the first man to 

 attempt to drive a dirigible by means of an engine. Giffard's 

 engine, however, was not sufficiently powerful as it developed 

 only three horse-power. His balloon was cigar-shaped, 144 feet 

 long, 40 feet in diameter at its thickest point. When no wind 

 was blowing he could drive the balloon at the rate of about 

 4 miles an hour. Experiments, however, continued to improve 

 the balloon and its engine. Electric motors driven by storage 

 batteries were substituted for the steam engine. It was not, 

 however, until the gasoline engine was introduced as the motive 

 power that real success came to the dirigible. The two men who 

 are conspicuously connected with the success of the modern 

 balloon are Santos-Dumont, a young Brazilian who was work- 



