Page:Popular Science Monthly Volume 92.djvu/443

 Popular Science Monthly

��427

��Another Inventor Renders a Service to Humanity

CONSIDER the picture on our right. In it we see a gearing-up attachment for a bicycle. It consists of a Y-shaped steel forging affixed at its three ends to the bicycle's frame. At its center revolve two sprocket wheels mounted on the same shaft. Over the smaller runs a chain r from the pedal sprocket, and from the larger another chain goes to the sprocket on the rear hub. The net result is to gear up the machine.

The attachment is supposed to increase a rider's speed by one- third, though lessening the former number of pedal revolutions required by one-half. But what about the immensely greater pushes on the pedals necessary? Such a contrivance may be useful on level boule- vards. But even a small hill would put it out of business.

���has a cylinder containing a cartridge and firing mechanism, with a fiat plate pro- jecting from the side and taking the part of the trigger. When the gopher comes burrowing along, shoving fresh dirt ahead of him, he touches off the trigger, and the gun goes off. This is hard on the animal, but affords keen pleasure to the boy who has sat by the mouth of the fresh burrow and waited for the wily gopher to make its appearance.

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��New attachment It also "gears up'

��to gear up a bicycle, the work you must do

��Making the Pesky Gopher Commit Suicide

CALIFORNIA and other western states have two sorts of game that are always in season. One is the gopher, which is not a turtle, as he is in the South, but a burrowing pest; the other is the ground squirrel. Both are nuisances, and both are under the sentence of death when it can be executed. To help in carrying out that sentence, a west- ern inventor has worked out a burrow gun. It

���Firing Pin

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���Pushing the dirt ahead of him, the gopher sets off the trigger and shoots himself

��Cutting Dow^n Engine Weight

lighter an ilane is the faster will it fly and the farther it will go. Hence the lighter the en- gine is the more successful will the airplane be. The one follows from the o t h er. In the development of the airplane motor into the remarka- ble machine it is to-day, this "weight efficiency" has become very high. It is little known how important was the part played in the development by a most simple device, originally invented for preventing the escape of gas from a breech-loading gun. This device is a cup-shaped piece of metal, now attached merely to the ends of the pistons of the airplane motor. Like its use in the gun, it checks the escape of the expanding gases. The greater the pressure of an explosion in the engine cylinders, the harder will the edges of the metal cup be pressed against the walls of the cylinders. Hence the less chance will there be of the gases leaking around the sides of the piston. The power in every portion of the exploding gases is therefore used, and none seeps away.

Wait until we get to transmit- ting powerto airplanes wirelessly! Then a light electric-motor of great power can be used. New fields will open.

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��BlanK^ Discharge' Cartridge Opening

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