158 COAST ARTILLERY IN ACTION. 
we class the united effects of variation in powder, bad drill, temperature, 
atmospheric conditions, age of gun, and “ personal factor” of gun, a 
formidable array enough. If, however, we assume that the powder is 
good, and eliminate such preventable disturbing causes as bad ramming 
home, damp sponging, &c.,, we have what is called the “error of the 
day” left, which of course, in any particular gun, will have a certain 
effect on the muzzle velocity. It is useful to consider this effect by 
itself: and here, let me say, that I know it is impossible to consider 
these effects separately in actual action, but, as it is nob feasible, as I 
shall attempt to show, to correct fire properly ‘‘shot by shot,” it is 
proper that we should think out, before action, how the various dis- 
turbing causes affect the shooting, try to eliminate them as far as we 
can, and where this is impossible, to leave as little as may be to 
individual judgment in war time. 
In figs. 2 and 3 I have drawn the curves of range and elevation in 
Fia. 2. 
| 
; I i in 
9) 1000 2000 3000 4.000 3000 
the cases of the 6” B.L. (80-pr.) and the 10” R.M.L., each with two 
separate muzzle velocities. rom these curves it is seen how the muzzle 
velocity affects their range, and, as a practical example, I may say that 
two years ago, at Sandown, we constructed a range table from fig. 8, 
which gave us very good results. We were firing with reduced charges, 
but found that the indication of the published range table had always to 
