And yet so sensible were the Romans of the imperfection of valor without skill and practice, that, in their language, the name of an army was borrowed from the word which signified exercise. 36 Military exercises were the important and unremitted object of their discipline. The recruits and young soldiers were constantly trained, both in the morning and in the evening, nor was age or knowledge allowed to excuse the veterans from the daily repetition of what they had completely learnt. Large sheds were erected in the winter-quarters of the troops, that their useful labors might not receive any interruption from the most tempestuous weather; and it was carefully observed, that the arms destined to this imitation of war, should be of double the weight which was required in real action. 37 It is not the purpose of this work to enter into any minute description of the Roman exercises. We shall only remark, that they comprehended whatever could add strength to the body, activity to the limbs, or grace to the motions. The soldiers were diligently instructed to march, to run, to leap, to swim, to carry heavy burdens, to handle every species of arms that was used either for offence or for defence, either in distant engagement or in a closer onset; to form a variety of evolutions; and to move to the sound of flutes in the Pyrrhic or martial dance. 38 In the midst of peace, the Roman troops familiarized themselves with the practice of war; and it is prettily remarked by an ancient historian who had fought against them, that the effusion of blood was the only circumstance which distinguished a field of battle from a field of exercise. 39 It was the policy of the ablest generals, and even of the emperors themselves, to encourage these military studies by their presence and example; and we are informed that Hadrian, as well as Trajan, frequently condescended to instruct the unexperienced soldiers, to reward the diligent, and sometimes to dispute with them the prize of superior strength or dexterity. 40 Under the reigns of those princes, the science of tactics was cultivated with success; and as long as the empire retained any vigor, their military instructions were respected as the most perfect model of Roman discipline.