346 Mr. J. Prescott on the 



the Mark VI. bullet, we find 



1 = 2600, 



^=6000, 



tio=2118, 



X 1 = 1800 feet (when u=1060). 



When X is less than 1800 feet 



x 

 X7=41710 1300 --l)— 38-77 X, . (35) 



and when X is greater than 1800 feet 



x 



Xy = 483900 6 3000 -221-8X-423900* . (36) 



The jump is 



; = - s^x x 41710 + 38-78 minutes, 



= -32'-08 + 38'-78, 



= 6'*7. 



The value of! I above was deduced directly from the range 

 table as in the case of the Mark VII. bullet. Then l x was 

 calculated by assuming that the ratio of l x to / is the same 

 as for the Mark VI. bullet. This ratio is, of course, the same 

 for all shot. Thus, for the Mark VI., 



4840 

 Ji=ggx 2600=5992, 



which is so near 6000 that it does not matter which value 

 we use. 



30. It is worth while to notice that, since / and l x are each 

 proportional to the weights of shot which have the same 

 diameters, we could have deduced their values for one 

 bullet from those for the other bullet and the weights of the 

 bullets. The weights of Marks VI. and VII. are given in 

 the ' Musketry Regulations ' as 215 grains and 174 grains 

 respectively. Consequently, for the Mark VI. bullet, we find 



Z=2100x^ = 2595, 

 174 



21 5 

 Z l = 4840x —=5980, 



assuming that I and l± for Mark VII. bullet are correct. 



