“Eudoxes… not only based the method [of exhaustion] on rigorous demonstration… but he actually applied the method to find the volumes (1) of any pyramid, (2) of the cone, proving (1) that any pyramid is one third part of the prism which has the same base and equal height, and (2) that any cone is one third part of the cylinder which has the same base and equal height. Archimedes, however, tells us the remarkable fact that these two theorems were first discovered by Democritus, though he was not able to prove them (which no doubt means, not that he gave no sort of proof, but that he was not able to establish the propositions by the rigorous methods of Eudoxes. Archimedes adds that we must give no small share of the credit for these theorems to Democritus… another testimony to the marvellous powers, in mathematics as well as in other subjects, of the great man who, in the words of Aristotle, "seems to have thought of everything"…. Democritus wrote on irrationals; he is also said to have discussed the question of two parallel sections of a cone (which were evidently supposed to be indefinitely close together), asking whether we are to regard them as equal or unequal… Democritus was already close on the track of infinitesimals.”
Achimedes (1920)
Help us to complete the source, original and additional information
Thomas Little Heath 46
British civil servant and academic 1861–1940Related quotes

p, 125
On the Sizes and Distances of the Sun and the Moon (c. 250 BC)

this implies the use of similar triangles in the way that the Egyptians had used them in the construction of pyramids
Achimedes (1920)

W. W. Rouse Ball, A Short Account of the History of Mathematics (1893, 1925)

Source: The Subtle Art of Not Giving a F*ck (2016), Chapter 4, “The Value of Suffering” (p. 86)
Part II. Of the Extent of Sensible Knowledge.
The Physiology of the Senses: Or, How and what We See, Hear, Taste, Feel and Smell (1856)