244. CAUSES OF DRIFT. 
So that in the golf ball, at all events, the drift must be owing to the 
cushioning. I feel that [am rather in a minority of one in taking that 
opinion ; everybody seems to be adhering to the gyrostatic action, but 
I think myself that the cushioning must, in some cases at all events, 
have a certain amount of effect. 
CAPTAIN E. S. COOPER, R.A., then exhibited the apparatus that he had 
made to show the result of gyrostatic action. 
REPLY. 
MAJOR-GENERAL OWEN—I think what Colonel Bainbridge said with 
regard to drift may be accounted for very likely by his explanation, 
which I think is accurate, namely that the projectiles have now much 
higher velocity of rotation and move more steadily, and therefore the 
drift is not so wide. 
Major MacMahon’s suggestion as to photography of the shot is cer- 
tainly, I think, an excellent one. A photograph of a bullet passing 
through a plate is the most wonderful thing, and was shown here I 
think some short time ago. I allude to the action of photography in 
showing the currents of air round the shot, which you cannot see with 
your eyes, and I do not see why you should not get some very good 
results by taking photographs of a shot at different points in the 
trajectory. 
Both Major MacMahon and Major Mackinlay said that after all every- 
thing depends on facts. I quite agree as to that. The facts that I have 
given you speak for themselves; if they are not sufficient then you 
must judge of that ; but so far as regards the last table, that General 
Nicholson gave me, showing the extraordinary increase of drift at these 
higher angles, I do not profess to offer any particular opinion. I 
merely state the fact here that the drift increases in a much higher pro- 
portion than the time of flight. I have not gone into the reasons for 
this proportion of the time of flight to the drift, beyond suggesting that 
the rolling effect may be considerable. What Captain Mansell has said 
may perhaps offer an explanation of the extraordinary fact of the left 
deflection of some projectiles fired at high angles which fall base first ; 
but if a shot falls base first whether it deflects to the right or to the 
left is not of much consequence, because it isa useless projectile with 
a percussion fuse. No shells should be fired at high angles unless they 
have a sufficient rotation to keep them steady in flight ; it is no use 
trusting to wild results, no matter in which direction they fall. 
{ will only say about a golf ball that, like a billiard ball or anything 
else of the kind, if you hit it in a certain direction you give it a certain 
rotation ; it will not twist one way or the other unless it has a rotation. 
Té will not drift without having a particular motion one way. 
I will not detain you longer, gentlemen. JI am very much obliged to 
you all for listening so attentively to me, although the subject is such 
an old one. I shall be very glad if it leads to any useful result so far 
as regards the future of artillery practice.* (Applause.) 
* Norr.—The Rey. F. Bashforth, formerly Professor of Applied Mathematics to the 
Advanced Class of Royal Artillery Officers at Woolwich, ard one of the highest authori- 
ties on scientific questions relating to the motions of projectiles from guns, in writing 
to me after this lecture, says : ‘‘I do not see what there is to object against the explana- 
tion of Magnus. It seems to me to be simple and complete, and well illustrated by the 
gyroscope. J always adopt the theory, and speak of it as a thing settled.” 
