The regiment of artillery comes out from barracks in one long column, perhaps--unless one battery or a greater proportion of the whole has further to travel than the batteries which take the straightest road. For, if there are two or more parallel roads leading from the point of departure to the destination, if it is possible for any considerable part of the journey to divide up an artillery regiment into separate batteries, this is done. The civilian has no conception of the length of line on the road which an artillery regiment of ten batteries would take up, nor can one who has not experienced the dust of a military march understand what sort of cloud the last battery of ten would have to march in. The column goes out as a whole, but as soon as possible first one battery and then another turns off from the main route. If there are only two alternate routes, then each alternate battery turns off, leaving sufficient interval between the rest for the dust of one to settle before the next shall come along. If there are more than two roads, all are used, for the more a long column can be broken up into separate units for a day's march, the sooner will the units of the column reach their destination. The fact that the larger a body of men is, the slower it moves, is one well known to military authorities, though civilians and even many military men would be prepared to dispute it. It will be seen to be incontrovertible, though, if one realises that the pace of any body of men which keeps together as one whole is the pace of the slowest unit, and, moreover, that when a long column is in progress, not all its units can keep exactly the same pace as the head of the column. Consequently there occur a series of checks in the body of the column; here and there crowding forward occurs, and then the units of the column concerned in the crowding have to halve in order to rectify this--or at least have to check their pace for the time. The check may travel from the centre of the column right down to its rear, and then there are gaps which have to be corrected, for when a check occurs it is always prolonged just a little too long a time--and then the head of the column has to check in order for the rear to catch up. And, the longer the column, the more of these irritating little checks there will be, with a net consequence that the column will take relatively longer to pass a given point or to arrive at a given spot.