REQUIRED FOR THE ATTACK OF A MODERN FORTRESS. 
91 
any particular supplement required, consequent upon the determination 
of details, being afterwards made out and sent to complete the train 
without confusion or trouble. 
The strength and composition of a siege train, as regards ordnance, 
has been arrived at in various ways. Some, basing their estimate upon 
the classes into which fortresses have been divided, have fixed the train at 
the maximum necessary for the reduction of a first class fortress, leav¬ 
ing the number to be reduced for any other class ; others have estimated 
it at so much per front, which amounts to much the same as the preced¬ 
ing mode ; while others again have preferred to fix a unit which can be 
multiplied, as requisite, for any particular fortress. 
The latter method is a convenient arrangement for peace administra¬ 
tion, and in war furnishes a means of readily making up the numbers of 
the train to any extent; but it is necessary that the numbers and compo¬ 
sition of the unit be based upon those of the total train required for a 
particular class of fortress, or the whole will be faulty. 
It appears, therefore, that the only true way of arriving at the strength 
and composition of the siege train for the attack of a modern fortress 
is to take what may be regarded as a typical fortress and estimate the 
train most suitable for its reduction under modern conditions, checking 
the results obtained, so far as may be, by known facts and finally, for 
convenience of administration, fixing a unit. 
As a typical fortress we must select one on the polygonal trace, 
<c which assures to the artillery an action more direct and effective over 
the ground of attack than the bastioned trace, -which has lost its 
importance in the manner in which artillery has progressed, so that, 
to-day it is condemned to the second place with S.B. guns and M.L. 
small arms,”* and it seems preferable to choose one of small size of the 
first class ;f in which view' we cannot take better than that described by 
Colonel Brialmont, in his “ Traite de Fortification Polygonale," 
constructed upon a regular decagon, with side of 360m. (393 yards.) J 
On the investment of a fortress, previous to the arrival of a siege 
train, the besieger cannot maintain himself within the most effective 
ranges of the fortress, because of the loss and exertion which it would 
entail and because his field artillery would not have sufficient ammuni¬ 
tion to keep up a constant fire day and night; hence, unless the defender 
has lost all energy, the besieger remains in such a position that the main 
body of his out-posts are not exposed to the fire of the artillery of the 
fortress. || 
Under modern conditions, “it may be assumed, therefore, that the 
defender finally succeeds in pushing forward his out-posts to a distance 
of from 1000 to 2000 paces beyond the fortress, whilst the besieger's 
line of out-posts can seldom hold its position within 3000 paces and as 
# Brialmont, Traite de Fortification Polygonale. 
f The German fortresses have by a recent decision, been classified, as :—I., fortresses 
with first-class armament, as Strasburg', Posen, &c.; II., fortresses with second-class 
armament, as, Bitche, Thionville, &c.; III., works for coast defences, as Memel, &c.— 
Revue d’Artillerie, February, 1877. 
X “ The trace of Antwerp ( i.e . polygonal of 1000 m. side), retains all its peculiar qualities 
when applied to fronts of 300 to 400 m.”—Brialmont, Traite de Fortification Polygonale. 
|| See, “ On Sieges,” by Kraft, Prince of Hohenlohe-Ingelfingen. 
