which project two arms, each provided with a screw that serves for the lateral adjustment of the gun. These screws are so arranged as to allow for an oscillating motion of the gun through any distance up to 15 deg. The tripod mounting, used for naval as well as land purposes, is shown in Fig. 2, which illustrates the two barrel gun complete. The five barrel gun, Fig. 3, is shown mounted on a similar tripod. The length of this weapon over all is 53.5 inches, the barrels (Henry system) are 33 inches long, with seven grooves of a uniform twist of one turn in 22 inches. [Illustration: Fig. 2.--TWO BARREL GARDNER GUN.] Gardener's five barrel gun in the course of one of the trials fired 16,754 rounds with only 24 jams, and in rapid firing reached a maximum of 330 shots in 30 seconds. The two barrel gun fired 6,929 rounds without any jam; the last 3,000 being in 11 minutes 39 seconds, without any cleaning or oiling.--_Engineering_. [Illustration: Fig. 3.--FIVE BARREL GARDNER GUN.] * * * * * CLIMBING TRICYCLES. The cycle trade is one which has been developed with great rapidity within the last ten years, and, like all new industries, has called forth a considerable amount of ingenuity and skill on the part of those engaged in it. We cannot help thinking, however, that much of this ingenuity has been misplaced, and that instead of striving after new forms involving considerable complication and weight, it would have been better and more profitable if manufacturers had moderated their aspirations, and aimed at greater simplicity of design; for it must be remembered that cyclists are, as a rule, without the slightest mechanical knowledge, while the machines themselves are subject to very hard usage and considerable wear and tear in traveling over the ordinary roads in this country. We refer, of course, more especially to tricycles, which in one form or another are fast taking the place of bicycles, and which promise to assume an important position in every day locomotion. Hitherto one of the chief objections to the use of the tricycle has been the great difficulty experienced in climbing hills, a very slight ascent being sufficient to tax the powers of the rider to such an extent as to induce if not compel him in most instances to dismount and wheel his machine along by hand until more favorable ground is reached. To obviate this inconvenience many makers have introduced some arrangement of gearing speeds of two powers giving the necessary variation for traveling up hill and on the level. We noticed, however, one machine at the exhibition which seemed to give all that could be desired without any gearing or chains at all. This was a direct action tricycle shown by the National Cycle Company, of Coventry, in which the pressure from the foot is made to bear directly upon the main axle, and so transmitted without loss to the driving wheels on each side, the