Suppose, he says, the gas were compressed to one-twentieth part of its bulk, which would mean a pressure within its receiver of 300 lbs. per square inch, and that each receiver had a capacity of 1 cubic foot, while for safety sake it was made of steel plates one-twentieth of an inch thick, then each receiver would weigh 10 lbs., and to liberate 1,000 feet clearly a weight of 500 lbs. would have to be taken up. Now, when it is considered that 1,000 cubic feet of hydrogen will only lift 72 lbs., the scheme begins to look hope less enough. But when the question of the pumping apparatus, to be worked by hand, is contemplated the difficulties introduced become yet more insuperable. The only feasible suggestion with respect the use of compressed gas is that of taking on board charged cylinders under high pressure, which, after being discharged to supply the leakage of the balloon could, in an uninhabited country, be cast out as ballast last. It will need no pointing out, however, that such an idea would be practically as futile as another which has gravely been recommended, namely, that of heating the gas of the balloon by a Davy lamp, so as to increase its buoyancy at will. Major Baden-Powell has aptly described this as resembling "an attempt to warm a large hall with a small spirit lamp." In any future attempt to reach the Pole by balloon it is not unreasonable to suppose that wireless telegraphy will be put in practice to maintain communication with the base. The writer's personal experience of the possibilities afforded by this mode of communication, yet in its infancy, will be given. CHAPTER XXV. THE MODERN AIRSHIP--IN SEARCH OF THE LEONIDS. In the autumn of 1898 the aeronautical world was interested to hear that a young Brazilian, M. Santos Dumont, had completed a somewhat novel dirigible balloon, cylindrical in shape, with conical ends, 83 feet long by 12 feet in diameter, holding 6,500 cubic feet of gas, and having a small compensating balloon of 880 cubic feet capacity. For a net was substituted a simple contrivance, consisting of two side pockets, running the length of the balloon, and containing battens of wood, to which were affixed the suspension cords, bands being also sewn over the upper part of the balloon connecting the two pockets. The most important novelty, however, was the introduction of a small petroleum motor similar to those used for motor tricycles.