Relation of the Three Arms

We shall only speak of the three principal arms: Infantry, Cavalry, and Artillery.

We must be excused for making the following analysis which belongs more to tactics, but is necessary to give distinctness to our ideas.

The combat is of two kinds, which are essentially different: the destructive principle of fire, and the hand to hand or personal combat. This latter, again, is either attack or defence. (As we here speak of elements, attack and defence are to be understood in a perfectly absolute sense.) Artillery, obviously, acts only with the destructive principle of fire. Cavalry only with personal combat. Infantry with both.
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The principal results we obtain from the whole of these considerations, are:

1 That infantry is the chief arm, to which the other two are subordinate.

2 That by the exercise of great skill and energy in command, the want of the two subordinate arms may in some measure be compensated for, provided that we are much stronger in infantry; and the better the infantry the easier this may be done.

3 That it is more difficult to dispense with artillery than with cavalry, because it embodies the chief principle of destruction, and its mode of fighting is more amalgamated with that of infantry.

4 That artillery being the strongest arm, as regards destructive action, and cavalry the weakest in that respect, the question must in general arise, how much artillery can we have without inconvenience, and what is the least proportion of cavalry we require?

[Note: Clausewitz bases his conclusions on the following data. The infantry musket could be fired about three times a minute and its effect was decisive up to 200 yards; its extreme range was about 1200 yards, so that in attacking, troops might begin to suffer loss when within that distance of the enemy. Artillery fire with round shot was still effective at 2000 yards but only became accurate at 1000 yards. With case shot, guns could sweep the ground from 400 yards -- and case contained about as many bullets as modern shrapnel of equal calibre -- i.e. a six-pounder case weighed about 12 lbs, a twelve-pounder case 24 lbs. Guns could be and were often double-shotted, and since at such close quarters, relaying after each shot was unnecessary, they could be fired up to ten rounds a minute. Howitzers formed part of every field battery and fired shell; they were principally used for setting fire to buildings and firing over the heads of advancing troops. Frederick the Great had already proposed to keep up an army Reserve of forty heavy howitzers for preparing his decisive attacks.

Owing to the deterioration of horse flesh, the consequences of the long wars, the efficiency of cavalry was very low. Except by the British, the charge at a gallop was considered too dangerous to be practised. The Napoleonic cavalry masses once started could no longer be manoeuvred or rallied, and generally exhausted their energy in an advance over 1500 yards of ground. * * *