374 Mr. J. Prescott on the 



any other ; and i£ we know the drift at one 

 results give us the drift at all other ranges. 



78. The numbers in the first and third columns under 

 " Drift" in the accompanying table give the values of 



/-l QP 



MY 



for the Marks VI. and VII. bullets, and the numbers in the 

 second column are reduced from those in the first column so 

 as to give 7 feet at 1500 yards for Mark VI. All sorts of 

 estimates of drift are given by different people. In the 

 1909 Edition of the 'Musketry Regulations' the drift is 

 stated to be 7 feet at 1500 yards. In Fremantle's ' Book 

 of the Rifle,' it is stated that the 1898 Edition of the 

 4 Musketry Regulations ' gives the drift as 11 inches 

 at 1000 yards, and 23 inches at 1200 yards. If we take 

 7 feet to be correct at 1500 yards for the Mark VI. bullet, the 

 table gives the drift at 1000 yards and 1200 yards as 23 inches 

 and 40 inches respectively. It must be remembered, how- 

 ever, that the shape of the bullet will affect/, and therefore 

 affect the drift. If, therefore, the 1898 and the 1909 

 Editions are referring to different bullets, no comparisons 

 can be made between the statements in the two Editions. 

 But we can compare the two values of the drift given in the 

 1898 Edition for different ranges, for we are told that the 

 muzzle velocity of the bullet to which these results refer is 

 2037, which is very little different from the muzzle velocity 

 given for the Mark VI. bullet in the 1909 Edition. If 

 11 inches were the correct drift for the Mark VI. bullet at 

 1000 yards, then the correct drift at 1200 yards, according 

 to our table, would be 19 inches instead of 23 as given. 

 The difference is not outrageous when we consider the diffi- 

 culty of the observation. 



79. In Fremantle's book other estimates of the drift are 

 given. Mr. R. L. Tippins's estimates are 10 inches at 

 500 yards and 4 feet at 1000 yards. The ratio of these is 

 4*8, whereas the corresponding ratio for the Mark VI. 

 bullet is 8"2, a rather big difference. Mr. John Rigby gave 

 10 inches at 1000 yards, which agrees very well with the 

 estimates given in the 1898 Edition of the 4 Musketry 

 Regulations,' but not at all well with the estimate in the 

 1909 Edition. Possibly these different estimates apply to 

 widely different rifles and different bullets, and may, 

 therefore, not be so discordant as they appear. Besides, it 



