82 Miracles Ahead! 



degrees Fahrenheit.) Smaller radiators are recessed in the pro- 

 peller hub to keep the blades free of ice. 



Another invention long in use but now more highly devel- 

 oped is the supercharger. 



If you have ever been on a high mountain you will remem- 

 ber that the "thinness" of the air forced you to breathe harder 

 and deeper. The lungs are flexible enough to make it possible, 

 within certain limits, to compensate for the thinness of the 

 air and get enough oxygen by breathing in more air. This is 

 nature's way of "supercharging" the human engine. 



To understand the all-important supercharger we should 

 first remember that we live at the bottom of a vast ocean of 

 air. Since the pressure of the air upon the outside of our bod- 

 ies is equalized by the internal pressures of the body, we often 

 forget that air has weight and exercises pressure. Designers of 

 internal-combustion engines are very much aware that the air 

 exerts a pressure of fourteen and seven-tenths pounds per 

 square inch at sea level. 



Because the air at higher altitudes contains less oxygen per 

 cubic foot, and there is less pressure available for pushing the 

 air into the cylinders, the power of a gasoline engine declines 

 in relation to altitude. At twenty thousand feet a cubic foot 

 of air weighs only about half as much as a cubic foot at sea 

 level. If the engine is to get the same air pressure at twenty 

 thousand feet as at sea level, we must give it twice as much of 

 the thinner air. This is what the supercharger does. When the 

 engine "gets out of breath" at high altitudes the supercharger 

 forces extra air into its cylinders. 



The turbosupercharger was perfected by Dr. Sanford B. 

 Moss of General Electric. Since one part of the device oper- 

 ates in an arctic sixty-below-zero while the other spins in a 

 blistering 1,500 degrees of heat, the turbosupercharger is an 

 engineering masterpiece. 



