The fact is that pictures which are unlike reality ought not be approved, and even if they are technically fine, this is no reason why they should offhand be judged to be correct, if their subject is lacking in the principles of reality carried out with no violations.

Leave a cavity behind the [wall] facings, and on the inside build walls two feet thick, made of red dimension stone or burnt brick or lava in courses, and then bind them to the fronts by means of iron clamps and lead. The beds and builds, all settling equally and bonded at the joints, will not let the work bulge out, nor allow the fall of the face walls which have been tightly fastened together.

Some people do indeed say that Eratosthenes could not have inferred the true measure of the earth. Whether true or untrue, it cannot affect the truth of what I have written on the fixing of the quarters from which the different winds blow.

But I, Caesar, have not sought to amass wealth by the practice of my art, having been rather contented with a small fortune and reputation, than desirous of abundance accompanied by a want of reputation.

Economy denotes the the proper management of materials and of site, as well as a thrifty balancing of cost and common sense in the construction of works. ...the architect does not demand things which cannot be found or made ready without great expense. For example: it is not everywhere that there is plenty of pitsand, rubble, fir, clear fir, and marble... Where there is no pitsand, we must use the kinds washed up by rivers or by the sea... and other problems we must solve in similar ways.

The [engineer] should be equipped with knowledge of many branches of study and varied kinds of learning, for it is by his judgement that all work done by the other arts is put to test. This knowledge is the child of practice and theory.

A harmonious design requires that nothing be added or taken away.