34'^ THE CONQUEST OF THE AIR. 



of the Aiken. The notice was : — 



"13 July, at 12.30 p.m., latitude 82 deg, 2', longitude 15 deg. 5' 

 East. The voyage is rapid towards East 10 deg. South. All is well. 

 This is the 3rd pigeon post. Andree." 



Let us imagine the end of this fateful voyage. The loss of 

 the two guide ropes and thus of 700 kgs. of ballast soon placed 

 the aeronauts at the mercy of the elements. The loss of gas 

 made the balloon sink more and more. The last guide rope and 

 the sails became useless and had to be dropped in order to get 

 into higher regions and more favourable air currents. Still, the 

 balloon soon dropped again, the last of the ballast had to be 

 sacrificed. Then followed the instruments, all unnecessary equip- 

 ment, provisions, and yet the balloon dropped. Probably this 

 happened near the peninsula Kola. As a last resource, perhaps 

 when safety was almost in sight, the basket reached the icy sea. 

 It had to be sacrificed and the aeronauts clung to the wooden ring 

 of the balloon. Even this did not increase the upward pressure 

 of the balloon sufficiently to carry it to the land, and the adven- 

 turers found a grave in the icy sea. On July 17th of the same 

 year Captain Lehmann of the steamer Dortrecht saw to the North 

 of Kola, a dark object in the sea, and birds flying to and from it. 

 It was in latitude 69 deg. 38' and longitude 35 deg. 34'. Each 

 gust of wind seemed to sway the floating island backwards and 

 forwards. In all probability this was the ill-fated balloon. Unfor- 

 tunately, when a mile away, and seeing that no human beings 

 were on it, the Captain turned his vessel. 



I shall now deal with airships. The shape of the airship 

 should be such that the air resistance becomes a minimum. A 

 sphere has a greater volume, proportionately to its surface, than 

 a body of any other shape. To drive a sphere through the atmos- 

 phere requires half the power needed to propel a circular plane of 

 equal diameter flatways on. The cigar-shaped form ofl'ers a good 

 deal less resistance than this ; but it has an envelope that is heavy 

 relatively to the volume of gas imprisoned. Its efficiency may be 

 augmented by a general increase in dimensions — the proportions 

 being constant — as the doubling of surface area of the envelope 

 far more than doubles the cubical contents. 



Experiments have shown that a hemispherical prow and a 

 conical tail give the best results as regards minimising air resist- 

 ance. It is much less important to avoid a blunt prow than to 

 keep the lines of the after-part fine, since the resistance of air to 

 being pushed aside is small as compared with the " suck " of a 

 badly-shaped stern. 



Major G. O. Squier, of the U.S. Army Signal Corps, laid it 

 down that the power consumed in propelling a displacement 

 vessel supported by air or water at any constant speed is con- 

 sidered as being two-thirds consumed by skin-resistance and one- 

 third by head-resistance ; and that a dirigible balloon carrying 

 the same weight, other things being equal, may be made to travel 

 about twice as fast as a boat for the same power, or to travel at 

 the same speed with the expenditure of about one-eighth of the 

 power. As there are practically always currents in the air, reach- 

 ing at times a velocity of 20 and 30 miles an hour, a dirigible 



