470 



reille: anti-aircraft firing 



may be its trajectory, to the time marked on the time-scale of 

 the fuse. 



But this is true only for clock-fuse. For the ordinary fuse 

 the time of bursting is determined by the duration of combustion 

 of a certain length of a communicating tube; this tube carries 

 from length to length a time-scale which indicates the time which 

 this combustion will take in the atmosphere near the earth. 



A Burst with clock'fuze at time 

 3' " ' ordinary fuze set 

 Fig. 3. 



For example, a fuse set at ten seconds burns for ten seconds 

 before bursting, if the region in which the combustion takes 

 place is noimal. Transport the fuse to another place in which 

 for example, the air is more rare, that is to say, less dense, and 

 instead of lasting ten seconds, the combustion will last eleven 

 or twelve. 



It follows from this, that the locus of the points of burst 

 for a given fuse setting is not the isochrone curve corresponding 

 to an equal thne of flight. In the high regions of atmosphere the 



