I made, also, three important observations. The first was, that as a general rule, the larger the bodies were, the more rapid their descent; --the second, that, between two masses of equal extent, the one spherical, and the other of any other shape, the superiority in speed of descent was with the sphere; --the third, that, between two masses of equal size, the one cylindrical, and the other of any other shape, the cylinder was absorbed the more slowly.

Since my escape, I have had several conversations on this subject with an old school-master of the district; and it was from him that I learned the use of the words 'cylinder' and 'sphere.' He explained to me --although I have forgotten the explanation --how what I observed was, in fact, the natural consequence of the forms of the floating fragments --and showed me how it happened that a cylinder, swimming in a vortex, offered more resistance to its suction, and was drawn in with greater difficulty than an equally bulky body, of any form whatever.*

*See Archimedes, "De Incidentibus in Fluido." --lib.2.