Subsequently Dr. Berson, in company with Dr. Suring, ascending from Berlin, attained an altitude of 34,000 feet. At 30,000 feet the aeronauts were inhaling oxygen, and before reaching their highest point both had for a considerable time remained unconscious. In 1901 a new aeroplane flying machine began to attract attention, the invention of Herr Kress. A novel feature of the machine was a device to render it of avail for Arctic travel. In shape it might be compared to an iceboat with two keels and a long stem, the keels being adapted to run on ice or snow, while the boat would float on water. Power was to be derived from a petrol motor. At the same period M. Henry Sutor was busy on Lake Constance with an air ship designed also to float on water. Then Mr. Buchanan followed with a fish-shaped vessel, one of the most important specialities of which consisted in side propellers, the surfaces of which were roughened with minute diagonal grooves to effect a greater grip on the air. No less original was the air ship, 100 feet long, and carrying 18,000 cubic feet of gas, which Mr. W. Beedle was engaged upon. In this machine, besides the propellers for controlling the horizontal motion, there was one to regulate vertical motion, with a view of obviating expenditure of gas or ballast. But by this time M. Santos Dumont, pursuing his hobby with unparalleled perseverance, had built in succession no less than six air ships, meeting with no mean success, profiting by every lesson taught by failures, and making light of all accidents, great or small. On July 15th, 1901, he made a famous try for the Deutsch prize in a cigar-shaped balloon, 110 feet long, 19,000 cubic feet capacity, carrying a Daimler oil motor of 15-horse power. The day was not favourable, but, starting from the Parc d'Aerostation, he was abreast of the Eiffel Tower in thirteen minutes, circling round which, and battling against a head wind, he reached the grounds of the Aero Club in 41 minutes from the start, or 11 minutes late by the conditions of the prize. A cylinder had broken down, and the balance of the vessel had become upset. Within a fortnight--July 29th--in favourable weather, he made another flight, lasting fifteen minutes, at the end of which he had returned to his starting ground. Then on August 8th a more momentous attempt came off. Sailing up with a rapid ascent, and flying with the wind, Santos Dumont covered the distance to the Tower in five minutes only, and gracefully swung round; but, immediately after, the wind played havoc, slowing down the motor, at the same time damaging the balloon, and causing an escape of gas. On this Santos Dumont, ascending higher into the sky, quitted the car, and climbed along the keel to inspect, and, if possible, rectify the motor, but with little success. The balloon was emptying, and the machine pitched badly, till a further rent occurred, when it commenced falling hopelessly and with a speed momentarily increasing.