THE ROYAL ARTILLERY INSTITUTION. 
It will be observed that he quotes from the official book from which 
I have extracted Table Y. 
Again, at page 79 he makes the following comments 
“ Another point should be considered in firing guns with equal eleva¬ 
tions : the gun which has the quickest recoil in reality throws higher 
than the other. This may be explained by a well-known mechanical 
principle. Suppose GV to represent the rate and direction of the 
muzzle velocity of a shell, GR that of the velocity of recoil; completing 
the parallelogram GR V V , and drawing the diagonal G V', then G V' 
represents the actual rate and direction of the muzzle velocity, tending 
to throw the shell higher than the gun is laid. This is on the supposition 
that the recoil commences before the shell is clear of the muzzle. 
Again, if the recoil is checked, the gun and carriage have a tendency 
to rotate on the trail, tending also to increase the elevation. In both 
these cases the gun which had the liveliest recoil would actually throw 
the highest. A difference in the preponderance of guns, the carriages 
on which they are mounted, as well as the nature of the ground on 
which they are fired, would probably exert some influence on the actual 
line of fire. 
“It is probably owing to some of the above reasons that the 3‘6-in. 
gun, when laid at 5° and 10° respectively (the same as the 3‘3-in. gun), 
threw higher than the latter, as the respective times of flight for that 
elevation clearly indicate (see Table Y.) The recoil of the 3‘3-in. gun 
was sensibly less than that of the 3*6-in.; and since the recoil was 
checked in both cases at 5° and 10° elevation, the 3*6-in. gun had a 
greater tendency to rotate round the trail than the 3‘3-in., and conse¬ 
quently threw higher and ranged farther. If it had been possible to 
ensure both guns being fired at 5°, the 3'3-in. gun would have ranged 
the farthest.” 
It would have been more correct had the author said “ in theory ” 
instead of “ in reality,” as I shall presently show. 
On the whole, we may gather from the above passages that the author is 
endeavouring to explain away the longer ranges given by the 3*6-in. gun 
on the suppositions—that the recoil of the 3‘6-in. gun was checked at 2°, 
whereas that of the 3‘3-in. gun was free; that the recoil with the 3‘6-in. gun 
was quicker than that with the 3'3-in., and that this caused the former 
gun to throw highest; and that either a difference in the preponderance 
of the guns, the carriages on which they were mounted, or the nature of 
the ground on which they were fired, caused the 3‘6-in. gun to throw 
higher, and consequently range further. 
Now, had the range given at 2° elevation on this occasion by the 
3‘6-in. gun been of an exceptional character) there might be. some force 
30 
