In the middle ages, infantry was considered of little importance, the combat being principally among the knights and cavaliers. The introduction of gunpowder caused a change in the method of fighting, but it was effected gradually. For a long time only clumsy cannon were used, which, however, made great havoc among the formations in mass still retained. Rude arquebuses were then introduced, and improvements made from time to time; but even so late as the 17th century the ancient arms were retained in a large proportion. They did not disappear entirely until the invention of the bayonet in the 18th century. This contributed as much as the use of firearms to change the formations of battle. In the 16th century the number of ranks had been reduced from ten to six; at the end of the reign of Louis XIV. the number was four; Frederick the Great reduced it to three. With this number the wars of the French Republic and Empire were conducted, until at Leipsic, in 1813, Napoleon's army being greatly diminished, he directed the formation in two ranks, saying that the enemy being accustomed to see it in three, and not aware of the change, would be deceived in regard to its numbers. He stated also that the fire of the rear rank was dangerous to those in front, and that there was no reason for the triple formation. In this judgment military authorities have since concurred, and the two-rank formation is almost universally adopted. Russia is the only civilized power which places men in masses on the battle field. Formations in column are used when necessary to carry a particular local position, even at a great expenditure of life. But the usual mode of combat is that adopted by Napoleon. Our battles have been almost universally fought in this manner. The rebels have probably used the formation in column more frequently than the Northern troops. The non-military reader can easily perceive that formations in mass are more subject to loss from the fire of artillery and from that of small arms even at considerable distances, and are less able to deliver their own fire. Our old regular army consisted of ten regiments of infantry, two of cavalry, two of dragoons, and one of mounted rifles, of ten companies each, and four artillery regiments of twelve companies each. Two companies each of the latter served as light artillery--the companies alternating in this service. There was also a battalion of engineers.