202 
FIELD ARTILLERY FIRE. 
1. That except in cases where actual penetration of cover is re¬ 
quired, or when time does not permit of the setting of time 
fuzes, the action of time shrapnel is more effective than that 
of percussion shrapnel, and, as a rule, it is easier to obtain 
good effect with it. 
2. That the angle of opening of the shell is from 12 degrees at 
short ranges to 18 degrees at long ranges. 
3. That it is impossible to observe from the battery how far back 
from the target the shell are bursting, but if we know that 
the trajectory of the shell is correct, we can, by observing 
the height of the burst above the line of sight and referring to 
the slope of descent, as given in the range table, ascertain, if 
we wish to do so, the exact distance that our shell are bursting 
short of the target. 
4. That the height that we wish to see a shell burst at, when using 
it against an extended formation is, in feet, two-thirds of the 
number of hundreds of yards in the range, i.e. if the range 
is 3000 yards we wish to see the shell burst 20 feet up in the 
air. Another way o£ measuring the height of burst, and very 
easily done with a telescopic sight, is to measure the angle be¬ 
tween the point of burst and the point aimed at, in the above 
case this would be eight minutes. At targets having a small 
front, such as a gun, or against deep formations, such as a 
column where depth of effect is required, it is desired to burst 
the shell closer up and the distance is placed at half the above, 
in the above example it would be 10 feet and 4 minutes respec¬ 
tively. Also when using time shrapnel against troops behind 
parapets it is useful to get a burst as close up as possible in 
order to get the extra searching power given by the angle of 
descent plus the semiangle of opening of the lower half of the 
cone of dispersion. 
These two angular measures are universal for all ranges. 
We may therefore say that if we know the trajectory to be 
correctly established and we see the shell bursting at 8 or 4 
minutes above the target, as required, we shall know that they 
are bursting at the right place and need not trouble ourselves 
about how far back they are from the target. 
If we were to start firing time shrapnel at once we could not, except 
at very short ranges, see whether they were bursting in the right place 
or not or even if they were short or over the target. It is therefore 
necessary, before we can get an effective fire of time shrapnel, to arrive 
at two things. 
1. The correct amount of elevation required, i.e. to establish the 
trajectory. 
2 . The correct length of fuze required to burst the shell at the 
proper point in that trajectory. 
The process of finding the above is termed “RANGING.” 
