The explanation consists in this, that by far the greater number of convoys derive more security from the strategic situation in general, than any other parts exposed to the attacks of the enemy, which bestows on their limited means of defence a very much increased efficacy. Convoys generally move more or less in rear of their own army, or, at least, at a great distance from that of the enemy. The consequence is, that only weak detachments can be sent to attack them, and these are obliged to cover themselves by strong reserves. Added to this the unwieldiness itself of the carriages used, makes it very difficult to carry them off; the assailant must therefore, in general, content himself with cutting the traces, taking away the horses, and blowing up powder-wagons, by which the whole is certainly detained and thrown into disorder, but not completely lost; by all this we may perceive, that the security of such trains lies more in these general relations than in the defensive power of its escort. If now to all this we add the defence of the escort, which, although it cannot by marching resolutely against the enemy directly cover the convoy, is still able to derange the plan of the enemy’s attack; then, at last, the attack of a convoy, instead of appearing easy and sure of success, will appear rather difficult, and very uncertain in its result.
But there remains still a chief point, which is the danger of the enemy’s army, or one of its corps, retaliating on the assailants of its convoy, and punishing it ultimately for the undertaking by defeating it. The apprehension of this, puts a stop to many undertakings, without the real cause ever appearing; so that the safety of the convoy is attributed to the escort, and people wonder how a miserable arrangement, such as an escort, should meet with such respect. In order to feel the truth of this observation, we have only to think of the famous retreat which Frederick the Great made through Bohemia after the siege of Olmütz, 1758, when the half of his army was broken into a column of companies to cover a convoy of 4,000 carriages. What prevented Daun from falling on this monstrosity? The fear that Frederick would throw himself upon him with the other half of his army, and entangle him in a battle which Daun