cavalry, so that the whole force would amount to 16,800 foot and 1800 horse. Skill in the selection of a spot for a camp (_capere locum castris_) was ever considered as a high quality in a general, and we find it recorded among the praises of the most renowned commanders that they were wont in person to perform this duty. Under ordinary circumstances, however, the task was devolved upon one of the military tribunes, and a certain number of centurions appointed from time to time for the purpose. These having gone forward in advance of the army until they reached the place near which it was intended to halt, and having taken a general survey of the ground, selected a spot from whence a good view of the whole proposed area might be obtained. This spot was considerably within the limits of the contemplated enclosure, and was marked by a small white flag. The next object was to ascertain in what direction water and fodder might be most easily and securely provided. These two preliminary points being decided, the business of measuring out the ground (_metari castra_) commenced, and was executed, as we learn from various sources, with graduated rods (_decempedae_) by persons denominated _metatores_. In practice the most important points were marked by white poles, some of which bore flags of various colours, so that the different battalions on reaching the ground could at once discover the place assigned to them. [Illustration: A, praetorium.--B, tents of the tribunes.--C, tents of the praefecti sociorum.--D, street 100 feet wide.--E, F, G, and H, streets 50 feet wide.--L, select foot and volunteers.--K, select horse and volunteers.--M, extraordinary horse of the allies.--N, extraordinary foot of the allies.--O, reserved for occasional auxiliaries.--Q, the street called Quintana, 50 feet wide.--V P, via principalis, 100 feet wide.]