Popular Science Monthly 



51 



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 



