Speed, therefore, is the aim of most manufacturers. They see that the aeroplane must, if it is to compete commercially with land or sea transit, provide a means of locomotion more rapid than any which at present exists; and they recognise, also, that speed offers—at any rate at present—a solution of the problem of all-weather flying. But there are, as has been hinted, difficulties in the way of large increases in speed. Two hundred miles an hour through the air is, frequently, cited as the ideal to be aimed at. So far, with a specially-built racing machine, a speed of approximately a hundred miles an hour has represented the maximum attained. Such machines are, however, more or less "freaks"; the best results obtained with ordinary machines being from sixty-five to seventy miles an hour. Higher speeds still might be thought to be merely a question of increasing horse-power. But other considerations enter into the question. A high-speed machine has, it must be remembered, to start away from the ground, and land again at the end of a flight; its actual passage through the air is not the only point to be considered. With a racing monoplane, for example, the small size of its supporting wings, and the slight camber upon them, necessitate its moving over the ground at a very high speed before it can obtain the necessary "lift" to get into the air; and then comes the question of returning to the ground again. These fast machines will only glide at comparatively high speeds. A problem arises, therefore, as to the landing chassis which will withstand the shock of high-speed landings—that is to say, on anything save perfectly smooth ground. Apart from the question of the skill of the pilot, in effecting a safe descent at such high speeds—and this is a factor seriously to be reckoned with—the running-wheels and skids of a machine will not endure the strain of a landing on anything like a rough surface. Thus, were speeds to be pushed, say, to a hundred and fifty miles an hour, under present conditions of flying, and with any existing method of building landing mechanism, accidents would be likely to happen, when airmen came to the point of effecting a descent. Also to be reckoned with, is the question of increasing the structural strength of machines in order to meet the wind pressure of very high speeds. III. Variable-speed aeroplane—Plans for constructing aircraft of this type—Advantages of such a machine. As regards the problem of a fast, and yet reliable aeroplane, which is an especially important one from the military point of view, seeing that machines will need to operate over all sorts of country during a campaign, the view is now taken, by eminent manufacturers, that something in the nature of a variable-speed aircraft will need to be devised.