Page:The Works of Archimedes.djvu/194
in setting them side by side both with my former investigations and with those of the theorems of Eudoxus on solids which are held to be most irrefragably established, namely, that any pyramid is one third part of the prism which has the same base with the pyramid and equal height, and that any cone is one third part of the cylinder which has the same base with the cone and equal height. For, though these properties also were naturally inherent in the figures all along, yet they were in fact unknown to all the many able geometers who lived before Eudoxus, and had not been observed by any one. Now, however, it will be open to those who possess the requisite ability to examine these discoveries of mine. They ought to have been published while Conon was still alive, for I should conceive that he would best have been able to grasp them and to pronounce upon them the appropriate verdict; but, as I judge it well to communicate them to those who are conversant with mathematics, I send them to you with the proofs written out, which it will be open to mathematicians to examine. Farewell.
I first set out the axioms[1] and the assumptions which I have used for the proofs of my propositions.
Definitions.
1. There are in a plane certain terminated bent lines (καμπύλαι γραμμαὶ πεπερασμέναι)[2], which either lie wholly on the same side of the straight lines joining their extremities, or have no part of them on the other side.
2. I apply the term concave in the same direction to a line such that, if any two points on it are taken, either all the straight lines connecting the points fall on the same side of the line, or some fall on one and the same side while others fall on the line itself, but none on the other side.
- ↑ Though the word used is ἀξιώματα, the "axioms" are more of the nature of definitions; and in fact Eutocius in his notes speaks of them as such (ὅροι).
- ↑ Under the term bent line Archimedes includes not only curved lines of continuous curvature, but lines made up of any number of lines which may be either straight or curved.