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gas, he will begin to fall; while, if he throws out too much, the balloon will become too light and go too high. Suppose the balloonist throws out just enough. Soon the cloud will cease to hide the sun. The gas heats up again to its first temperature and regains its old lifting power. But, having less to lift by the weight just thrown out, the balloon now shoots up higher. Its gas dilates, so that some of it escapes or must be sacrificed to save the balloon from going too high. Then, having overshot its equilibrium and lost too much gas, you will begin descending—only to condense more gas, and to sacrifice more ballast; and the trouble recommences!’’

In these words M. Santos-Dumont unconsciously foretold the occasion of the catastrophe which terminated these experiments at Monaco; for once, in spite of precautions and chiefly because he was alone and unaided, the suddenly overheated hydrogen carried him too high.

These montagnes russes (‘‘shoot the chutes’’) of spherical ballooning, M. Santos-Dumont has always avoided over land as much as possible by the play of his shifting weights, which enable him to lift or lower the nose of his cigar-shaped balloon, and so drive it diagonally upward or downward by means of his propeller force. This manœuver of itself makes enough work for one man. To be freed from it, except when one desires to mount or descend, and to go forward on a chosen level automatically, is the ideal realizable from maritime guide-roping.

Over land, where there are level plains without the troublesome and really dangerous drawbacks of trees, rocks, fences, and buildings, and telegraph or trolley-wires, the guide-rope might be thought useful to the dirigible balloonist; but over the uninterrupted stretches of the sea, these Monaco experiments have proved it to be a true stabilisateur. Its very slight dragging resistance through the water is out of all proportion to the considerable weight of its floating extremity. According to its greater or less immersion, therefore, it ballasts or unballasts the airship. The balloon is held by its weight down to almost a fixed level over the waves, yet without danger of its being drawn into contact with them. Every extra foot of guide-rope floating means so much less weight for the balloon to lift and so much automatic remounting into the air. In this way an incessant little tugging toward and away from the waves is produced, an automatic ballasting and unballasting accomplished without loss of ballast.

Wind and Speed

LET us acknowledge, once for all, that the flight of February 10th, and the one which succeeded it on February 12th, furnished the most beautiful popular spectacle ever afforded by aërial navigation. Not even the sensational trips over the housetops of Paris from Saint-Cloud to the Eiffel Tower and back offered such a demonstration of the airship’s power and the navigator’s control over it. On each occasion M. Santos-Dumont directed his course far out to sea, only returning after a round trip much longer than the one which gave him the Deutsch Prize. On each occasion the guide-rope stabilisateur held the balloon at the constant level altitude desired, so that the navigator was left free to pursue his course without wasting time, ballast, gas, or propeller force. On each occasion—and this is very prettily if accidentally shown by three photographs—the navigator continued on his straight course despite adverse winds which, in one case, developed into a moderate squall.

In the photograph marked ‘‘Wind A,’’ the airship is seen driving up the coast toward the Italian frontier, while two sailing-yachts directly beneath him are obviously scudding in just the opposite direction, in front of what any yachtsman would call a stiff breeze. Farther to the right the smoke of a small steamer, violently blown to the right, indicates the force of the breeze at the moment.

In the photograph marked ‘‘Wind B,’’ the airship is seen to be on the point of quitting (not returning to) the Bay of Monaco in the teeth of a wind that blows far back the smoke of two steamers.

In the photograph marked ‘‘Wind C,’’ the airship is pursuing its course head on into a wind that keeps the sail-boats’ three canvasses straining in the opposite direction.

These photographs, taken by a professional simply desirous of making a good picture, afford the most complete kind of answer to those who question the airship’s ability to make way against the wind. It takes a stiff wind to send a great yacht kicking up foam with its sails bellied to their straining-point.

It was during the flight of February 12th that the intrepid navigator of the air persisted most sensationally against the wind, and attained his greatest distance from the Aërodrome. One petroleum and two steam-launches, together with three well-manned rowboats, had been stationed at intervals down the coast, to pick him up in case of accident. The steam chaloupe of the Prince of Monaco, carrying his Highness, the governor-