So is engineering a science so far as it investigates the general principles of fortification, and also artillery, in analyzing the principles of gunnery; but both are arts when considered with reference to the practical rules for the construction, attack, and defence of forts, or for the use of cannon.
This distinction has not always been observed by writers on this subject, and some have asserted that strategy is the _science_, and tactics the _art_ of war.

This is evidently mistaking the general distinction between science, which investigates principles, and art, which forms practical rules.
In popular language, however, it is usual to speak of _the military art_ when we refer to the general subject of war, and of _the military sciences_ when we wish to call attention more particularly to the scientific principles upon which the art is founded.

We shall here consider the military art in this general sense, as including the entire subject of war.
As thus defined, the military art may be divided into four distinct branches, viz.: 1st.

_Strategy_; 2d.

Fortification, or _Engineering_; 3d.