370 



Mr. J. Prescott on the 



the two sets of results for the Mark VII. bullet may be 

 regarded] as a justification of the law of resistance used in 

 tliis paper. 



Wind Deviation when Velocity of Wind is 10 miles per hour. 



Eange 

 in yards. 



Wind Deviation. 









100 



Mnrk VI. bullet. 



Mark VII. bullet. 



Mark VII, bullet. 



1*5 inches. 



1*33 inches. 



134 inches. 



200 



61 



5-7 



5-8 



300 



144 



13-6 



13-6 



400 



26-9 



25-5 



25-6 



500 



3-66 feet. 



3-49 feet. 



3-51 feet. 



600 



547 



531 



534 



700 



7-63 



7-63 



7-69 



800 



101 



10-35 



10-44 



900 



12-8 



1344 



13-45 



1000 



15-7 



16-8 



16-8 



1100 



19-0 



20-6 



20-4 



1200 



22-5 



24-7 



24-3 



1300 



26-3 



29-1 



28-6 



1400 



303 



339 



33-2 



1500 



347 



39-0 



38-3 



1600 



39*4 



44-7 



44-0 



1700 



44-4 



50-7 



498 



1800 



49-8 



57-3 



562 



1900 



55 6 



642 



631 



2000 



618 



71-8 



70-6 



72. The value of ^ that, we should get by integrating; both 

 sides of equation (93) gives the amount of angular deflexion 

 of the line of flight of the shot from the path that an equally 

 resisted spherical shot would follow if no wind were blowing. 

 This deflexion occurs then with every projectile from a 

 rifled gun, and the amount will be the same at the same 

 range for all equal projectiles fired from similar guns. The 

 angle e affects the range only and need not be considered, 

 since it has only the same effect as a slight alteration in the 

 resistance. But the angle rj indicates a deviation from the 

 vertical plane containing the axis of the gun, and this is 

 something that can be observed as wind deviation can be 

 observed. 



73. Now 



^~ sr~~zr 



dr] 

 dT 



Hence, equation (93) gives 



dr) 

 dH 



=t/ p - 1 )^{' J ^( 2 +/x 3 +/)^ + ■• •}■ < 103 ) 



