Napoleon calls the infantry the _arm of battles_ and the _sinews of the army_. But if it be acknowledged, that, next to the talent of the general-in-chief, the infantry is the first instrument of victory, it must also be confessed that it finds a powerful support in the cavalry, artillery, and engineers, and that without these it would often be compromised, and could gain but a half success. The French infantry is divided into one hundred regiments of three battalions each, a battalion being composed of seven companies. There are also several other battalions of chasseurs, zuaves, &c., being organized especially for service in Africa, and composed in part of native troops. In our own army we have eight regiments of infantry, each regiment forming a single battalion of ten companies. The flank companies are intended for light infantry. In all properly organized armies the infantry constitutes from three-fourths to four-fifths of the entire active force in the field, and from two-thirds to three-fourths, say about seven-tenths of the entire military establishment. In time of peace this proportion may be slightly diminished. _Cavalry._--The use of cavalry is probably nearly as old as war itself. The Egyptians had cavalry before the time of Moses, and the Israelites often encountered cavalry in their wars with their neighbors, though they made no use of this arm themselves until the time of Solomon. The Greeks borrowed their cavalry from the Asiatics, and especially from the Persians, who, according to Xenophon, held this arm in great consideration. After the battle of Platea, it was agreed by assembled Greece that each power should furnish one horseman to every ten foot-soldiers. In Sparta the poorest were selected for this arm, and the cavalry marched to combat without any previous training. At Athens the cavalry service was more popular, and they formed a well-organized corps of twelve hundred horsemen. At Thebes also this arm had consideration in the time of Epaminondas. But the cavalry of Thessaly was the most renowned, and both Philip and Alexander drew their mounted troops from that country. The Romans had made but little progress in this arm when they encountered the Thessalians, who fought in the army of Pyrrhus. They then increased their cavalry, but it was not numerous till after their wars with the Carthaginians. Scipio organized and disciplined the Roman cavalry like that of the Numidians. This arm was supplied from the ranks of the richest citizens, and afterwards formed an order intermediary between the Senate and the people, under the name of _knights_.