‹‹‹ Vitr. 10.11.2 | Table of Contents | Vitr. 10.11.4 ›››
3A balista capable of throwing a stone of two pounds should have the hole (foramen) in the capital five digits wide; for a stone of four pounds, six digits; for a stone of six pounds, seven digits; for a stone of ten pounds, eight digits; for a stone of twenty pounds, ten digits; for a stone of forty pounds, twelve digits and nine sixteenths; for a stone of sixty pounds, thirteen digits and one eighth; for one of eighty pounds, fifteen digits; for one of one hundred and twenty pounds, one foot and a half and a digit and a half; for one of a hundred and sixty pounds, two feet; for one of a hundred and eighty pounds, two feet and five digits; for one of two hundred pounds, two feet and six digits; for one of two hundred and ten pounds, two feet and seven digits: and lastly, for one of two hundred and fifty pounds, eleven feet and a half.
3A ballista intended to throw a two-pound stone will have a hole of five digits in its capital; four pounds, six digits; and six pounds, seven digits; ten pounds, eight digits; twenty pounds, ten digits; forty pounds, twelve and a half digits; sixty pounds, thirteen and a half digits; eighty pounds, fifteen and three quarters digits; one hundred pounds, one foot and one and a half digits; one hundred and twenty pounds, one foot and two digits; one hundred and forty pounds, one foot and three digits; one hundred and sixty pounds, one foot and a quarter; one hundred and eighty pounds, one foot and five digits; two hundred pounds, one foot and six digits; two hundred and forty pounds, one foot and seven digits; two hundred and eighty pounds, one foot and a half; three hundred and twenty pounds, one foot and nine digits; three hundred and sixty pounds, one foot and ten digits.