On Architecture

13. Now let us turn our thoughts to the researches of Archytas of Tarentum and Eratosthenes of Cyrene. They made many discoveries from mathematics which are welcome to men, and so, though they deserve our thanks for other discoveries, they are particularly worthy of admiration for their ideas in that field. For example, each in a different way solved the problem enjoined upon Delos by Apollo in an oracle, the doubling of the number of cubic feet in his altars; this done, he said, he inhabitants of the island would be delivered from an offence against religion.

14. Archytas solved it by his figure of the semicylinders; Eratosthenes, by means of the instrument called the mesolabe.

Noting all these things with the great delight which learning gives, we cannot but be stirred by these discoveries when we reflect upon the influence of them one by one. I find also much for admiration in the books of Democritus on nature, and in his commentary entitled *xeiro/kmhta, in which he made use of his ring to seal with soft wax the principles which he had himself put to the test.