226 CAUSES OF DRIFT. 
of to the right, and should therefore deflect to the left, or, at any rate, 
more to the left than a pointed shot. Professor Magnus first pointed 
out the effect of the resistance of the air upon a flat-headed or 
cylindrical shot and after stating that their deviations would most 
probably be to the left, he says :—“ I understand the experiments have 
already been instituted with such cylindrical projectiles and their 
results have confirmed this conjecture.” 
Iam not aware what experiments Professor Magnus refers to here, 
but this conjecture had been confirmed by the results of practice at 
Shoeburyness, in November, 1858, with Whitworth flat-headed shot 
(not his later tapered form) showing, that five shot, fired at five degrees 
of elevation, all had left deflections varying from forty-five to seventy- 
two feet. The shots were fired from a 382-pr. gun, rifled on the 
Whitworth system, and giving right-handed rotatory motion to the 
shot ; the charge was 6-lbs., the ranges and deflections as below :— 
Round Range Deflection 
yds feet 
1 2240 66 left 
D 2090 B4 , 
3 2230 TA 6 
4 2180 GO 55 
5 2225 45 
In order to obtain some confimation, Captain (now Lieutenant-General) 
Fraser, R.A., kindly fired some flat-headed bullets from an Enfield rifle, 
against service ones, at a range of 300 yards, in the Royal Arsenal, in 
March, 1862; in a series of 6 of each, 4 of the flat-headed bullets 
deflected to the left, two very widely, the other two, slightly to the 
right, while the service bullets were very near the line of range, 
3 slightly right, and 3 slightly left. This was only a rough experiment, 
the flat-head being obtained by cutting off, and therefore shortening the 
service bullet, and the range was too short, for the flat-head would have 
required a much sharper twist to keep it steady, at a long range, still, 
the tendency of the drift to the left was apparent. 
Wishing, however, for more satisfactory results, I obtained leave to 
have some service shot fired from a 40-pr. Armstrong gun, against the 
same number of specially made cylindrical, or flat-headed projectiles.” 
Very calm days were selected for the practice, so that the results 
might be affected as little as possible by wind. 
Both service and special shot were fired at each day’s practice from 
the same 40-pr. Armstrong gun, mounted on a travelling carriage ; 
weight of piece 32-cwt., calibre 4°75-in., spiral (right-hand twist) 1 turn 
in 37: calibres, and number of grooves 56. 
* J attended this practice myself, and it was carried out by Major (now Major-General 
Sir H. J.) Alderson, R.A., then Assist.-Superintendent at Shoeburyness. The tables 
of the practice, and the remarks on the results, were given by me, in a paper on the 
“ Derivation of Hlongated Projectiles,” in proceedings of R.A. Institution, Vol. iv., 
page 180. 
