1893.) : Recent Literature. 457 
the students in the theory of light—natural and polarized. The value 
of the work to the student of polarized light lies in the fact that many 
experiments are described that aid one to gain a clear notion of double- 
refraction, of interference, and of the resolution of vibrations into two 
sets at right angles to each other, without compelling him to accept the 
conclusions of mathematical processes. Scattered between chapters 
dealing with the experimental data are others, in which these data are 
explained, and a few in which the theory of light vibrations is dis- 
cussed, the whole forming a logical exposition of the modern theory of 
light. 
Unfortunately for the reader, there are many clumsily-constructed 
sentences in nearly every chapter of the book, which need much close 
study before the meaning of their author can be discerned. This fact 
necessarily detracts from the delight with which the volume would 
otherwise be perused, but not so much so as would be the case were it 
not so compactly written. An immense amount of material is collected 
within its covers, and very little of this matter could well be spared by 
the student. A little more confidence might have been felt in the 
author’s statements, as representative of the most modern views of 
light specialists, had he given some evidence of his acquaintance with 
the wonderful grating of Rutherford and Rowland, instead of mention- 
ing only Noblet’s gratings and Barton’s buttons in his discussion in 
diffraction. The imperfections, however, are slight as compared with 
the abundant good qualities of the book. 
The volume is well printed and splendidly illustrated with a 
wealth of cuts and nine lithographic plates, of which four are beauti- 
fully colored. 
The student of light phenomena will find many of his difficulties 
in understanding the theory of his subject cleared away if he will care- 
fully examine the experiments described by Mr. Wright, and thor- - 
oughly digest the accompanying explanations—W. T. B. 
