376 



Mr. J. Prescott on the 



the range. For instance, the bullet has a drift 2*75 inches 

 at 500 yards range ; therefore the 3-inch shot will have a 

 drift 275 inches at 5000 .yards range. Again, a 12-inch 

 shot will have a drift 2416 inches, that is, 201 feet, at a 

 range of 16,000 yards. These results apply to solid shot, 

 and will need modification for hollow shot. 



81. Let us see what information we get about /and c by 

 assuming that the estimate of drift given in the 1909 

 Edition of the ' Musketry Regulations ' is correct for the 

 Mark VI. bullet. This gives 



11-2 



that is, 

 But 





7 feet, 



^^KdJ^ 1 * 00 *- ■ • (114) 



2ttK 2 

 ~ Ned' 

 Wc c 



c m 



n x m gBco K 2 o> 2ttKV 



Hence, equation (114) gives 



1-6 /-l 2ttK 2 _^ 

 9 / 9 Ned ' 

 Taking, as before, 





we get 



K 2 =^d 2 , N = 33, 



/-l d = 90 4 x 33^ 

 f c 16 * irgl 2 u 



= 0-614. . . 



(115) 



Here we have one equation connecting the two uncertain 

 quantities c and /. Corresponding values of e and / satis- 

 fying equation (115) are here arranged in tabular form: 



/. 



2 



3 



4 



5 



6 



CO 



c (inches) ... 



0-247 



0-329 



0-370 



0-395 



0-411 



0493 



We have here an upper limit for c. With the above 

 estimate of drift our theory leads us to the conclusion that c 

 cannot be greater than half an inch for the Mark VI. bullet. 



