LOGISTICS.

III.  We have defined logistics to be that branch of the military art which embraces all the practical details of moving and supplying armies.  The term is derived from the title of a French general officer, (major-general des logis,) who was formerly charged with directing the marches, encampments, and lodging of the troops.  It has been still further extended by recent military writers, and many of them now regard logistics as a distinct and important branch of the art.

We shall here consider logistics as including the military duties ordinarily attributed to the pay, subsistence, clothing, medical, hospital, and transportation departments; in fine, of all the civil and civico-military corps of the army.  We shall therefore discuss under this head, the preparation of all the necessary materials for fitting out troops for a campaign and for putting them in motion; the regulating of marches, convoys, the means of transport for provisions, hospitals, munitions, and supplies of all kinds; the preparation and protection of magazines; the laying out of camps and cantonments; in fine, every thing connected with preparing, moving, and guarding the impedimenta of an army.

The officers connected with this branch of service must consult with the engineers in every thing relating to the defence of their depots, magazines, camps, cantonments, communications, and the passage of rivers, and in all that relates to their connection with the attack and defence of places:  but in all that relates to strategy and tactics they must receive instructions directly from the chief of the staff of the army, who will have the general direction of every thing connected with logistics.  Before commencing the operations of the campaign, or beginning the execution of the plans decided upon at head-quarters, this officer should satisfy himself respecting the condition of the various materials belonging to the different departments of the army;—­the horses and horse equipments, carriages, caissons, ponton and artillery equipages, siege equipages, moveable hospitals, engineer and artillery utensils, clothing, and munitions of all kinds; he must supply whatever may be wanting, and provide means for the transportation of every thing.

Subsistence.—­The art of subsisting troops during active operations in a hostile country, is one of the most difficult subjects connected with war; and it is a question well worthy of study, both for the statesman and the warrior, how Darius and Xerxes, Philip and Alexander, in ancient times—­and the Greek emperors and the barbarians—­and, later still, the crusaders of the middle ages, contrived to support the immense masses of men which they led to war.

Caesar has said that war should be made to support war; and some modern generals have acted upon this principle to the extreme of supporting their armies entirely at the expense of the country passed over.  Others have adopted either in part or entirely the principle of regular magazines.