34:2 Mr. J. Prescott on the 



where d is the diameter of the shot in inches and K ? 

 Variable given in his tables. But we have assumed that 



t, WV 2 

 ±1= r . 



9 l 

 By equating the two values of R we find that 



W 10 9 





d 2 YK V ' 



When V = 2000 feet per sec. K v is given in Bashforth's 

 tables as 68'8. Also the weight of the Mark VII. bullet is 



jKfiQ of a pound, and its diameter about 0*303 of an inch. 



Therefore, 



174 x 10 9 



7000 x 0-303 2 x 2000 x 6SS 

 = 1967 feet. 



Taking 2000 as a rough value for I we find, from equa- 

 tion (5), that the horizontal distance travelled by the bullet 

 while u drops from 2440, the given muzzle velocity, ito 

 1060, is . ■ 



X=2000 log, g^ feet, 



= 1667 feet = 556 yards. 



Then the law does not change till the bullet has moved 

 more than 500 yards horizontally. 



24. The values of X and y in the following table are taken 

 from the l Musketry Regulations ' (1909 Edition), and the 

 values of s are calculated from them. 



X feet 



600 

 8'-0 

 4800 



900 

 l'l'-3 



10170 



1200 

 15'3 



18360 



1500 

 20'-2 



30300 





s 





Now, taking X=-=600, X' = 900, 8 = 300, equation (28) 

 gives 



mk _ 30300-36720 + 10170 _ 375 



Therefore, 



18360-20340 + 4800 282' 

 600 



Z _2 



k " \og e 3-75- log e 2-82 



= 2105 



(29) 



