72 
MINUTES OF PROCEEDINGS OF 
Fig-. 11. 
9. Breaching a Scarp by battering its upper hale. 
In fortresses of modern construction it is no longer considered suffi¬ 
cient to keep the cordon out of sight, and the line connecting the 
cordon and the top of the covering mass is inclined at a slope of 1 in 5, 
or even 1 in 4. If, therefore, the lowest point of impact is taken at 
half the height of the scarp, the angle of descent will be 15° to 20°, or 
more. In order to get at a scarp protected in this way by means of 
curved fire we are compelled, not only to reduce the charge consider¬ 
ably, but also to place the battery a long way off. Under such circum¬ 
stances the large vertical spread of the projectiles renders a systematic 
breaching out of the question, and we are obliged to content ourselves 
with effecting a breach by destroying the upper half of the scarp, 
supposing that the profile conditions allow this to be done. 
A Prussian writer* recommends that the portion of the scarp nearest 
the top be selected as the point to be fired at first, when heavier charges 
can be employed. In this case, when the scarp has been well cut up 
and knocked about, the mean point of impact can be gradually lowered 
by reducing the charge as the penetration of the projectiles increases. 
The latest experience gained at Graudenz shows that in this kind of 
breaching if the lowest point of impact be fixed at half the height of 
the scarp, there is no danger that lowering the point of impact will 
cause the penetration of the projectiles and their bursting effect to be 
prejudiced by the mound of masonry fragments and earth that collect 
in front of the lower portion of the scarp—as was the case at Strasburg 
in breaching Lunette No. 53, where the lowest point of impact was 
taken at about a third the height of the scarp. 
The French artillery, when breaching Fort Liedot on the Island of 
Aix in 1863, took the opposite course, in that they endeavoured, by 
employing small charges and high angles of elevation, to strike the 
scarp in the first instance at half its height, and afterwards, by increas¬ 
ing the charge and diminishing the elevation, to destroy the upper half 
of the masonry for the breadth of the breach. Lastly, employing full 
charges, they bombarded the highest portion of the scarp and the 
parapet, and thereby caused a downfall of the masonry and earth, thus 
* Witte. Artillerie-Lelire, III Tlxeil, 1873. 
