Page:Popular Science Monthly Volume 88.djvu/195

 Popular Science Monthly

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��A Windmill Which Always Turns in the Same Direction

WHEN the wind strikes a surface inclined at an angle to the direc- tion of the wind, the surface is displaced in a direction that depends upon the de- gree of inclination. Upon this well- known principle sailboats, windmills, and aeroplanes are built. When the wind comes in an opposite direction — that is to say, strikes the surface on the other side — it tends to displace it in the opposite direction. It would seem then to be impossible so to place a surface that it shall always move in the same direction no matter whence the wind comes. A French windmill maker, how- ever, has succeeded in solving the prob- lem. He makes a horizontal windmill with perpendicular vanes and axis re- volved by the planes without gearing.

The vanes are formed of many sheets of iron arranged in the form of a wheel. The wind on entering the wheel passes between the plates and produces motion, and the wind on issuing, dips along the general slope of the vane and produces motion in the same direction.

The wind is thus utilized going and coming. A\'hen the vanes are properly inclined, the power produced by this strange windmill is high, and the wind

����The roll of tape is sixty feet long. On

it is written one of the longest letters

ever mailed for two cents

��Puzzling windmill which always tiims in

the same direction, no matter how the

wind is blowing

that reaches nine-tenths of the wheel's diameter is set to work, no matter in what direction it is blowing.

An Island Made to Order

Hx^W'AHAN soil is being used to build up the small coral island in the Pacific Ocean known as the Midway and used as a relay station by a trans- Pacific cable company. A quantity of earth is taken there every three months by the schooner that is sent with food supplies for the operators. The task of building the island has progressed so far that if is now possible to keep a cow on the pasture.

The Longest Letter in the World

YOUR friends are always asking for long letters. To supply this demand a man in Los Angeles, California, has invented a little novelty that has cap- tured the fancy of visiting tourists.

It consists of a roll of paper tape sixty feet long. The paper is made to write on, and has a place for the name and address of the sender and receiver. It goes as first class mail for two cents, like any other letter, and can be mailed in any mail box.

These little "long letters" cause many a laugh and one can write a regular letter on the tape, by merely unrolling it as it is used up.

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