506 
PENETRATION OE EARTH AND MASONRY. 
Balloon 
observation. 
Instrumen¬ 
tal observa¬ 
tion. 
A Iteration in 
character of 
debris. 
Rate of 
breaching. 
Ripple para¬ 
pet s and 
screens. 
A series of successive apparent blinds would favour tlie conclusion 
that shell were being smothered. Water is most easily distinguished 
by the column thrown up. 
Balloons are a great assistance in preventing waste of shell if their 
car contains a really practised observer; but the view obtained from a 
balloon is so entirely different to what the eye is accustomed to that, 
without much practice in observation, information received from this 
source is apt to cause waste. A balloon looks over all obstacles, and 
the observer in it is frequently unaware of their existence. 
High ground in the neighbourhood may occasionally take the place 
of a balloon. 
Plane tables, theodolites, and very much rougher modes have been 
used with advantage to aid in ensuring the projectiles fired from 
howitzers falling in the right place, and it may be occasionally possible 
to get an observer, during darkness, hidden far to the front, in tele¬ 
phonic communication with the guns where he can actually see the 
attacked work. 
A practised eye soon detects whether the debris thrown up alters in 
character, and if the effect of shells signalled as correct is well noted, 
it is soon recognised that fire is falling off in accuracy. 
Where no means of giving an observer a more or less bird’s-eye 
view, or of getting a pair of eyes well to the front exists, the destruc¬ 
tion of well-concealed works becomes a difficult problem, and generally 
entails a vastly increased expenditure of ammunition. 
With well-organised fire, carefully checked by good observation, it 
has been shown that with an 8-inch R.M.L. howitzer, throwing a shell 
of 180 lbs. with a bursting charge of 25 lbs. of powder, it was reason¬ 
able to expect to form a breach through a thrown up earthwork, at 
reasonable ranges, at the rate of one foot in depth per round, including 
waste shell; the breach thus formed being a little less than the width 
of the crater made by the shell in the material. 
In 1887 having no funds at my disposal for the erection of target 
works, I was driven to throw up shingle in the most economical way I 
could to waste fire, and it was an object that the work should be very 
easily repaired after fire. My target work consisted of a number of 
ditches with the earth extracted from them thrown up between them. 
It was named by the men who constructed it the “ Ripple ” parapet, 
and though a small amount of earth was moved compared to the 
ordinary parapets, in a trial against a 30 feet solid work there was little 
to choose between them, the cause being that many shell passed through 
the thin crests doing little damage, and became wasted by bursting in 
the air in the intervals. 
The lesson gained is that defences should be constructed to waste as 
many shell as possible, while artillery fire must be economical in every 
sense to be truly effective. 
