No other European state has the dimensions of Russia, and in very few can a line of retreat 100 miles long be imagined. But neither will a power such as that of the French in 1812, easily appear under different circumstances, still less such a superiority in numbers as existed at the commencement of the campaign, when the French army had more than double the numbers of its adversary, besides its undoubted moral superiority. Therefore, what was here only effected at the end of 100 miles, may perhaps, in other cases, be attained at the end of 50 or 30 miles.
The circumstances which favour this mode of defence are—
1. A country only little cultivated.
2. A loyal and warlike people.
3. An inclement season.
All these things increase the difficulty of maintaining an army, render great convoys necessary, many detachments, harassing duties, cause the spread of sickness, and make operations against the flanks easier for the defender.
Lastly, we have yet to speak of the absolute mass alone of the armed force, as influencing the result.
It lies in the nature of the thing itself that, irrespective of the mutual relation of the forces opposed to each other, a small force is sooner exhausted than a larger, and, therefore, that its career cannot be so long, nor its theatre of war so wide. There is, therefore, to a certain extent, a constant relation between the absolute size of an army and the space which that army can occupy. It is out of the question to try to express this relation by any figures, and besides, it will always be modified by other circumstances; it is sufficient for our purpose to say that these things necessarily have this relation from their very nature. We may be able to march upon Moscow with 500,000 but not with 50,000, even if the relation of the invader’s army to that of the defender in point of numbers were much more favourable in the latter case.
Now if we assume that there is this relation of absolute power to space in two different cases, then it is certain that the effect of our retreat into the interior in weakening the enemy will increase with the masses.
1. Subsistence and lodging of the troops become more difficult—for, supposing the space which an army covers to increase in proportion to the size of the army, still the subsistence for the army will never be obtainable from this space alone, and everything which has to be brought after an army is subject to greater loss also; the whole space occupied is never used for covering for the troops, only a small part of it is required, and this does not increase in the same proportion as the masses.