100 Scientific Intelligence. 



Four lines, at 3746*06, 3767*34, 3850*12, 3888-07, have, so far 

 as our indications go, no modification produced whatever. The 

 lines at 3*722*72 and 3872*64 are so modified as to be quadruplets, 

 the central component which has its vibrations along the line of 

 force being a close double. There are several other lines con- 

 cerning which we have doubt, but most of the others examined 

 are clearly modified in the way described by Zeeman. We have 

 noted too that the separation of the side components of the trip* 

 lets seems to be most irregular; lines whose wave-lengths differ 

 by only a few Angstrom units have displacements which differ by 

 20 per cent at least. In short, there seems to be no regularity in 

 the separations produced. (Several of the above effects have 

 been observed by other investigators.) 



In studying the spectrum of cadmium we have observed that 

 the lines at 4678*37, 4800*09, 5086*06, which belong to the "sec- 

 ond subsidiary series," and the lines at 3467*76 and 3613*04 

 which belong to the "first subsidiary series," are all modified in 

 the normal manner; that is to say, in the manner described by 

 Zeeman, and by amounts which are no greater than for iron, but 

 that there seems to be no regularity in the separations produced, 

 either between the two series or between the lines of any one 

 series. 



We have been unable to extend our investigations into the 

 extreme ultra violet owing to the fact that the Nicol's prism 

 which we used in order to separate the components, absorbs the 

 waves beyond 3400. 



In the study of the spectra of zinc and of magnesium, we have 

 not yet obtained results which are worthy of note. 



10. An Elementary Course of Physics. Edited by Rev. J. C. P. 

 Aldous, M.A. 862 pp. London and New York, 1898. (Britannia 

 Series : The Macmillan Co.) — In this volume, the chapters devoted 

 to Mechanics, Properties of Matter, Hydrostatics, and Heat have 

 been prepared by the editor ; those on Wave Motion, Sound, and 

 Light, by W. D. Eggar ; and those on Magnetism and Electricity 

 by F. R. Barrell. The authors have certainly succeeded in giv- 

 ing a very satisfactory and attractive presentation of the subject 

 of physics from the elementary and somewhat popular side. In 

 many cases the subjects are introduced with a brief allusion to 

 the historical development which is sure to make the matter more 

 real to the student. Thus the opening paragraphs devoted to 

 motion begin with the mention of Newton's observation of the 

 falling apple; even a picture of the philosopher is added (perhaps 

 unnecessarily, in this case). The principles are stated through- 

 out in clear and simple language, and the frequent illustrations, 

 verbal and pictorial, are much to be commended ; the latter have 

 been for the most part freshly prepared for this volume. Math- 

 ematical expressions are largely avoided, which fact, while limit- 

 ing the usefulness of the book in certain obvious directions, makes 

 it all the more readable for the class of students for whom it has 

 been prepared. 



