In even greater measure is this true of the top. The top has been everybody's toy and must, therefore, at one time or another have piqued everybody's curiosity. Lagrange, Poinsot, Jacobi, not to mention other great names, have in turn paid their tribute; yet the top may be set spinning to-day, unhampered by a completed theory to account for its evolutions.
Among recent contributions we may refer in particular to Professor A. G. Greenhill's noteworthy papers... when one remembers that these complex curves reach only especially simple cases of motion, one may get some notion of the difficulty of the problem involved.
The reviewer is aware... he has given an imperfect account of this remarkable book. That Klein's researches constitute a splendid advance in dynamics of the rotation of a rigid body there can be no question. One cannot but hope that the outline given in these Princeton lectures may soon be expanded and put in shape more easily assimilated by persons more moderately versed in the theory of elliptic functions.
The boon of an appropriate lemma is ideal generosity, and not even a mathematician can scorn its mathematical elegance.
A man may be a thoroughgoing soldier enough on land; but put him in the foot ropes of the flying jibboom in a storm, and he is apt to cut a most ludicrous figure. Shift a physicist's foothold of Cartesian differential coordinates, suspend him over an abyss of non-Euclidean space, and he will kick sturdily. Poor policy this, for a missionary!