Page:Popular Science Monthly Volume 91.djvu/726

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��Popular Science Monthly

��peded has had its influence on naval archi- tecture. Who can forget the warships of twenty-five years ago, bulging masses of sponsons as they were? All these eccentric curves, which almost con- cealed the true lines of the hull, were intended to increase the firing efficiency of the guns.

The Gotha marks a similar step in the evolu- tion of the airplane. Be- cause of the difficulty of mounting guns on a flying machine, odd shapes are beginning to appear in the air. The need for an inverted channel through which a three-inch rapid- fire gun could fire with ease was most imperative in the two-motored Gotha bombing machine, relatively the slowest of all German airplanes. Such a craft is likely to be called upon to engage in a running fight. Fir- ing to the rear is not a new idea itself; but it has always been done over the top of the fuselage from the cockpit. There was left below the fuse- lage an immense dead angle in which a pursuing machine might securely attack.

No doubt the Gotha's tunneled tail will be imitated by the Allies; for their big bombing planes are even larger and slower than the Gotha. The number of guns that an air plane can carry are so limited by considerations of weight, that each must necessarily be so mounted as to secure the maximum efficiency. This is the point on which the Gotha shows its superi- ority.

By the adoption of a similar firing tunnel or vault for Zeppelins it is possible that the giant rigid dirigible which has dropped so low, recently, in the estimation of the German au- thorities, may be restored to military favor despite its vastly greater bulk and vulnerability when pitted against fast, elusive, fighting airplanes of later date, firing inflammatory bullets from machine guns.

���Trousered Legs Are Not Always What They Seem

HERE is a boon for the bow-legged man. It is a light, flexible structure which can be strapped around the leg above the knee to preserve the straight line of the trouser leg. The strap would take the place of his garter, the lower end of the brace device being fastened to the sock with an ordinary garter- clasp. To the con- necting strap a number of short lead struts are hinged. These are held projecting outward more or less horizontally from the leg. By adjusting the slope of these struts, the distance of the outer strap from the leg can be ad- justed at the different points and this regulates the "bulge." The struts " give" sufficiently to prevent discomfort.

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��Two straps held apart by adjust- able metal struts keep the outline of the trouser leg always straight

��Sidewalks Flushed

Without Disturbing

Parked Cars

CHICAGO has discov- ered a way to flush her sidewalks without dis- turbing the automobiles and other vehicles which are parked along the curbing. Two automobile tank trucks are used to clean the downtown section of the city every night through a pipe ex- tention to the discharge line as shown in the photograph below.

���Flushing the sidewalk from an overhead pipe leading from the tank truck in the street

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