His first ascension was full of incident: a storm was encountered; the clouds spread themselves between them and the map-like earth, so that nothing could be seen except the white, billowy masses of vapour shining in the sun; some difficulty was experienced in getting down, for the air currents were blowing upward and carried the balloon with them; the tree-tops finally caught them, but they escaped by throwing out ballast, and finally landed in an open place, and watched the dying balloon as it convulsively gasped out its last breath of escaping gas. After a few trips with an experienced aeronaut, Santos-Dumont determined to go alone into the regions above the clouds. This was the first of a series of ascensions in his own balloon. It was made of very light silk, which he could pack in a valise and carry easily back to Paris from his landing point. In all kinds of weather this determined sky navigator went aloft; in wind, rain, and sunshine he studied the atmospheric conditions, air currents, and the action of his balloon. The young Brazilian ascended thirty times in spherical balloons before he attempted any work on an elongated shape. He realised that many things must be learned before he could handle successfully the much more delicate and sensitive elongated gas-bag. In general, Santos-Dumont worked on the theory of the dirigible balloon--that is, one that might be controlled and made to go in any direction desired, by means of a motor and propeller carried by a buoyant gas-bag. His plan was to build a balloon, cigar-shaped, of sufficient capacity to a little more than lift his machinery and himself, this extra lifting power to be balanced by ballast, so that the balloon and the weight it carried would practically equal the weight of air it displaced. The push of the revolving propeller would be depended upon to move the whole air-ship up or down or forward, just as the motion of a fish's fins and tail move it up, down, forward, or back, its weight being nearly the same as the water it displaces. The theory seems so simple that it strikes one as strange that the problem of aerial navigation was not solved long ago. The story of Santos-Dumont's experiments, however, his adventures and his successes, will show that the problem was not so simple as it seemed. Santos-Dumont was built to jockey a Pegasus or guide an air-ship, for he weighed but a hundred pounds when he made his first ascensions, and added very little live ballast as he grew older. Weight, of course, was the great bugbear of every air-ship inventor, and the chief problem was to provide a motor light enough to furnish sufficient power for driving a balloon that had sufficient lifting capacity to support it and the aeronaut in the air. Steam-engines had been tried, but found too heavy for the power generated; electric motors had been tested, and proved entirely out of the question for the same reason.