472 reille: anti-aircraft firing 



twenty seconds a flying machine has time to change its course 

 in various sudden and unexpected ways, both as to altitude and 

 as to direction. The problem has nevertheless a probable solution 

 and this solution belongs to the domain of mathematical extra- 

 polation based on the laws of continuity, to wit: 



G gii"^ 



5 aircro-ft 



W horizontoLl plaint 



Fig. 4. 



A moving body that has covered, with uniform speed, a curve 

 ab in space during the time t should, at the end of a total time 



t + dt, reach a point c, such that ^i = ^ • This is nothing else 



but the equation of uniformity of speed. 



If the curve in space ab is given in terms of the parameter t 

 by the equations: 



' X =f, (t) 



y =h it) 



z =fsit) 



the coordinates of the extrapolated point c will be given by the 

 same equations by replacing t by t + dt. 



