[F]ew important steps in dynamical geology will be made until the methods for the accurate measurement of high temperatures and high pressures have n… - Carl Barus

Turning to Klein's little book, one is astonished in finding the most general aspects of the subject treated almost without computation and in so little space. ...It would have cost little to give the expanded form of the σ-function. ...Weierstrass's original notation was in terms of Abelian functions. The tremendous development of s is out of proportion with their application to natural phenomena. Meeting them rarely one forgets them. Memory peters out like the infinite series of a ζ-function.

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!

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.