Page:Popular Science Monthly Volume 92.djvu/67

 Popular Science Monthly

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��jets! His controls open or close the "boxes" above the jets just enough to keep him balanced. Foot levers manipulate a "verti- cal rudder" as in an airplane. This vertical rudder is visible just beneath the nearest box. Tilting it to one side or another enables the airman to keep his machine in the path of the jets. Attempts at de\asing practi- cal ground training machines for flyers have been made be- fore. Long ago the French con- structed a machine in which the candidate was placed high up on a pivot. It was the candi- date's task to balance the ma- chine by manipulating a con- trol pulled on sliding weights. These moved out laterally in four directions along arms some- what smaller than those illus- trated. This machine was interesting in principle, but it could not simulate actual flying conditions accurately, since weights will not move with the same un- certainty as air currents. The new ma- chine probably will be more satisfactory.

���The Largest Check in the World Was Easy to Cash

THE biggest check in the world is not the one made out recently by J. P. Morgan for some hundred mil- lions of dollars, but one made out for a mere five hun- dred and seventy- five dollars on pa- per twenty-two inches long and ten inches wide. The check was drawn by the Otterbein Men's Bible Class of the Grace Unit- ed Brethren Church of Carlisle, Pa., in favor of the new church build- ing fund. The

check is printed in gold and contains a photograph, in the left hand corner, of the pastor of the church.

��Excess water makes concrete ea

impairs its strength. So after the road is laid,

this roller is used to press the concrete "dry"

Squeezing the Excess Water Out of Newly Laid Concrete Roads

WERE it not for Captain J. J. Gail- lard, City Engineer of Macon, Georgia, excess water would still be re- garded as an unavoidable evil in building concrete roads. He has originated a finishing treatment for the concrete, which squeezes out a large amount of the water after the road has been laid. After the concrete has been roughly finished, a wide, heavy roller is drawn across the road. The weight of this roller re- moves the uneven spots in the road, and at the same time presses out the water that has lodged in the min- ute spaces in the sand and gravel of the concrete.

When this opera- tion is repeated many times, there is little water left. Especially is this so in the top surfaces of the road bed. The result is that where the wear on the road is the greatest, the concrete will set rigid.

���This, the largest check (in inches) ever made out, was given toward a church building fimd. It measures twenty-two inches in length

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