But at high exhaustions the free path becomes comparable with the dimensions of the glass bulb, and this equalization proceeds slowly.

Such slipping had shown itself at high exhaustions in the experiments of A.

This subject was investigated by Archimedes, who, by his "method of exhaustions," derived the principal results.

In his extant Conoids and Spheroids he defines a conoid to be the solid formed by the revolution of the parabola and hyperbola about its axis, and a spheroid to be formed similarly from the ellipse; these solids he discussed with great acumen, and effected their cubature by his famous "method of exhaustions."