prIn the magnificent and spacious Grecian city of Ephesus an antient law was made by the ancestors of the inhabitants, hard indeed in its nature, but nevertheless equitable. When an architect was entrusted with the execution of a public work, an estimate thereof being lodged in the hands of a magistrate, his property was held, as security, until the work was finished. If, when finished, the expense did not exceed the estimate, he was complimented with decrees and honours. So when the excess did not amount to more than a fourth part of the original estimate, it was defrayed by the public, and no punishment was inflicted. But when more than one-fourth of the estimate was exceeded, he was required to pay the excess out of his own pocket.
2Would to God that such a law existed among the Roman people, not only in respect of their public, but also of their private buildings, for then the unskilful could not commit their depredations with impunity, and those who were the most skilful in the intricacies of the art would follow the profession. Proprietors would not be led into an extravagant expenditure so as to cause ruin; architects themselves, from the dread of punishment, would be more careful in their calculations, and the proprietor would complete his building for that sum, or a little more, which he could afford to expend. Those who can conveniently expend a given sum on any work, with the pleasing expectation of seeing it completed would cheerfully add one-fourth more; but when they find themselves burdened with the addition of half or even more than half of the expense originally contemplated, losing their spirits, and sacrificing what has already been laid out, they incline to desist from its completion.
3Nor is this an evil which occurs in buildings alone, but also in the shows of gladiators in the Forum, and in the scenes of plays exhibited by the magistrates, in which neither delay nor hindrance is admitted, since there is a necessity for their being completed by a certain time. Thus the seats for viewing the shows, the machinery for drawing the Vela, and the contrivances for shifting the scenes, must all be prepared by a given day, that the people may not be disappointed. And in the preparation of all these much readiness and profound thought must be exercised, because they cannot be executed without machinery, and the application of varied and extensive studies.
4Since, therefore, this is the case, it does not seem foreign to our purpose, carefully and diligently to explain those principles on which a work should be formed previous to commencing it. But as neither the law nor custom compels the adoption of such a practice, and the prætors and ædiles are bound every year to provide the machinery for the sports, it appeared to me, O Emperor, highly expedient, as in the foregoing books I have treated on buildings, to explain in this which closes the treatise, the principles upon which such machines are constructed.