The composition of the various Head-Quarters, and the number and nature of the Units of Army Troops, and of the Units on the L. of C., will depend on the conditions of the campaign, which will vary according to the enemy to be encountered, the climate and nature of the theatre of war, and the character of the Lines of Operations and Communications. It was explained in the previous chapter that in order to allow of normal Establishments to be drawn up, the assumption is made that the war will take place in a civilized country and in a temperate climate. A _normal_ Line of Communications is also assumed, consisting of a Seaport or a Base, a railway from it 100 miles long, and two lines of road 30 miles long from Railhead to the Advanced Bases. The following pages show the composition of the whole Force and of the various Subordinate Commands forming it, as well as that of the various Head-Quarters, the “Army Troops,” and the Troops on the Lines of Communication. The Establishments of the various Fighting Units are also given, followed by a table of their strength in round numbers of officers, men, and horses actually belonging to the Unit. Some notes on the general principles on which the Establishments have been drawn up will first be given. A _Medical Officer_ is attached to each unit, and a _Veterinary Officer_ to each mounted unit. Two to five men of the _Medical Corps_ are attached to each unit, according to its strength. A _Bâtman_--that is, an officer’s servant or groom--is provided for each Officer, and a second one if he has more than one horse. Bâtmen are armed and trained soldiers, taken from the unit, and available for duty in its ranks. _Draught Horses_ are allotted as follows: six to each gun or ammunition-wagon, four to each wagon, and two to each cart. Spare horses are provided at the rate of 10 per cent. of the total. One _Driver_ is provided for each pair, and 10 per cent. of _spare drivers_ are added, but this number is 5 per cent. in the case of Divisional Ammunition Columns, and T. and S. Parks. Two _Trumpeters_, _Drummers_, or _Buglers_, are allotted to each Squadron or Company of Fighting Troops. The _Regimental Sergeant-Major_ is a Warrant Officer. There is one in each Cavalry Regiment, Infantry Battalion, and Artillery Brigade. EXPEDITIONARY FORCE COMPOSITION OF SUBORDINATE COMMANDS CAVALRY BRIGADE Head-Quarters. 3 Cavalry Regiments. CAVALRY DIVISION Head-Quarters. 4 Cavalry Brigades. _Cavalry Divisional Troops_: _Cavalry Divisional Artillery_: Head-Quarters. 2 Horse Artillery Brigades. _Cavalry Divisional Engineers_: Head-Quarters. 4 Field Troops. 1 Wireless Telegraph Company. 1 Transport and Supply Column. 4 Cavalry Field Ambulances. INFANTRY BRIGADE Head-Quarters. 4 Infantry Battalions. DIVISION