THE ROYAL ARTILLERY INSTITUTION. 
17 
ON THE DETEBMINATION OE BANGE TABLES FOB 
EIFLEE OBDNANCE. 
By COLONEL LEEROY, R.A., E.R.S. 
1. The Bange Tables in universal use in our service profess to give the 
true mean horizontal range of the projectile; that is to say, the distance 
from the gun at which the shot touches the horizontal plane on which the 
carriage is placed. Thus we see for point blank range, or 0° of elevation, 
a range assigned of 300 yds., or some such quantity, leaving it to be 
inferred that 0° elevation is proper for all distances up to 300 yds., unless 
we adopt the alternative that something less than 0 ° of elevation, i.e. a 
depression, is to be given to strike an object within that distance ; that 
this cannot really be the case is self-evident. The anomaly arises from 
inaccurate definition of the range of a shot: a gun is not fired at 300 yds., 
or indeed, generally speaking, at any other distance, to strike the ground, 
but to strike an object above the ground; and the elevation to be given 
must be such that the trajectory shall pass through the point aimed at, 
consequently giving a greater horizontal range than the distance to the foot of 
the object,—we acknowledge this in musketry fire, and it is the principle which 
regulates the sighting of all rifles. The irregularities of fire make the distinction 
practically of no importance at considerable distances; but it is far other¬ 
wise at short ranges, where the precision of rifled guns makes it possible to 
strike a small mark, and it becomes necessary to adopt the following precise 
definition of range:— 
( 1 ) By the range due to a given elevation } is meant the distance from the 
muzzle of the gun to the second intersection of the trajectory with the line of 
sight (the first intersection being close before the muzzle ). 
Note. —The following is extracted from the Heglement sur le service du canon de 4 ray6 de 
camjpagne systeme la Hitte, 1860. It is to he regretted that we have no term equivalent to but 
en blanc, as distinct from jportee, and are obliged to take the term range; hut it must he well 
observed that there is nothing inconsistent between this definition of range and the common 
sense of it, and nothing whatever to prevent the word in ordinary language being used to 
signify the distance to the first graze of the shot on horizontal ground. But then it should be 
understood that the tabular range is the distance to the object or target; and if the shot misses 
that object and goes further, or strikes, and passes through it to the ground, the range on the 
ground corresponds in the Table to a slightly larger angle,—to the angle in fact which would be 
given if the object intended to he struck were at the distance of the point actually struck. The 
Americans call the jportee de but en blanc the point blanlc range, we call it the line of metal range. 
When a gun is laid directly on an object by line of metal, it is said by them to belaid jpoint blank.* 
This definition is of course inconsistent with the use of disparts; with the Armstrong guns, which 
[VOL. III.] 
Gibbon’s ‘'Artillerists Manual," 1860, p. 226. 
3 
