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WEBSTER— BALLISTICS OF A GUN 



made at Krupp's), Hojel in Holland, and Krtipp in Germany, that 

 for velocities of over 300 meters per second the law is represented 

 with great exactness by a straight line. Although experimental re- 

 sults do not go above velocities of 1,200 meters/sec, I have felt no 

 hesitation in extrapolating for such values as are here used. In 

 Fig. I are shown, in Curve i, the values given by Siacci. In Curve 

 2, the values of the function K(v)^^f(v)/v', and in Curve 3 the 

 values of K{v) as given by Krupp. It is only fair to say that the 

 results of the French Commission de Gavre more nearly resemble 

 Curve 3 than Curve i. 



The use of the linear law (originally suggested by Chapel) has 

 been recommended by the Comte de Sparre in a paper published in 

 1901. 



Fig. 2. 



In order to expedite matters, a graphical chart was prepared 

 (Fig. 2) with abscissas denoting the velocity in meters per second, 

 containing straight lines and inclinations proportional to the densi- 

 ties of the air at different heights. On the right is a scale giving 

 the height above the earth and by following the line corresponding, 

 the resistance R is read off on the scale at the left. 



