‹‹‹ Vitr. 10.10.5 | Table of Contents | Vitr. 10.11.1 ›››
6All these proportions are appropriate; some, however, add to them, and some diminish them; for if the capitals are higher than the width, in which case they are called anatona, the arms are shortened: so that the tone being weakened by the height of the capital, the shortness of the arm may make the stroke more powerful. If the height of the capital be less, in which case it is called catatonum, the arms must be longer, that they may be the more easily drawn to, on account of the greater purchase; for as a lever four feet long raises a weight by the assistance of four men, if it be eight feet long, two men will raise the weight; in like manner arms that are longer are more easily drawn to than those that are shorter.
6These engines are constructed according to these proportions or with additions or diminutions. For, if the height of the capitals is greater than their width—when they are called “high-tensioned,”—something should be taken from the arms, so that the more the tension is weakened by height of the capitals, the more the strength of the blow is increased by shortness of the arms. But if the capital is less high,—when the term “low-tensioned” is used,—the arms, on account of their strength, should be made a little longer, so that they may be drawn easily. Just as it takes four men to raise a load with a lever five feet long, and only two men to lift the same load with a ten-foot lever, so the longer the arms, the easier they are to draw, and the shorter, the harder.