October 16, 1903.] 



SCIENCE. 



497 



meteorology of the northern hemisphere is 

 independent of that of the southern? To 

 settle that primary question we want a 

 synchronous chart for the globe. As long 

 as we are imable to watch the changes 

 in the globe we are to a certain extent 

 groping in the dark. A great part of the 

 world is already mapped every day, and 

 the time has now arrived when it is 

 worth while to consider what contributions 

 we can make towards identifying the dis- 

 tribution of pressure over the globe. We 

 may idealize a little by disregarding the 

 local peculiarities without sacrificing the 

 general application. I have put in the ex- 

 hibition a series of maps showing what ap- 

 proximation can be made to an isochronous 

 chart of the globe without special effort. 

 We are gradually extending the possibility 

 of acquiring a knowledge of the facts in 

 that as in other directions. With a little 

 enterprise a serviceable map could be com- 

 piled; and when that has been reached, 

 and when we have added to that what the 

 clouds can tell us, and when the work of 

 the aeronautical committee has so far pro- 

 gressed that we can connect the motion 

 of the upper atmosphere with the conditions 

 at the surface, when we know the real kine- 

 mr.tics of the vertical and horizontal mo- 

 tion of the various parts of a traveling 

 storm, we shall, if the universities will help 

 us, be able to give some rational explana- 

 tion of the.se periodic relations which our 

 solar physics friends are identifying for 

 us, and to classify our phenomena in a 

 way that the inheritors of Kepler's achieve- 

 ments associated with us in this section 

 may be not unwilling to recognize as sci- 

 entific. W. N. Shaw. 



SCIENTIFIC BOOKS. 

 Introduction to the Rarer Elements. B.v 

 Philip E. Browning, Ph.D., Assistant Pro- 

 fessor of Chemistry, Yale Universit.v. New 

 York, John Wiley & Sons. Pp. viii + !■''"• 



" This small volume, prepared from material 

 used by the author in a short lecture course 

 given at Yale University, is intended to serve 

 as a convenient hand-book in the introductory 

 study of the rarer elements; that is, of those 

 elements which are not always taken up in a 

 general course in chemistry. No attempt has 

 been made to treat any part of the subject 

 exhaustively, but enough references have been 

 given to furnish a point of departure for the 

 student who wishes to investigate for him- 

 self. Experimental work has been included 

 except in the case of those elements which 

 are unavailable, either because of their 

 scarcity or because of the difficulty of iso- 

 lating them." 



The above excerpt is taken from the preface 

 of this excellent work. The unusual interest 

 in the so-called rare earths in very recent 

 years has been marked. Doubtless many in- 

 structors have wished for a guide to be placed 

 in the hands of students. To be sure, those 

 who have been engaged with investigations 

 along these lines have had at hand Truehot's 

 ' Les Terres Rares,' Herzfeld and Korn's 

 ' Chemie der seltenen Erden ' (upon which 

 this book is in a measure founded), as well as 

 such specialized brochures as Koppel'e ' Die 

 Chemie des Thoriums,' Giesel's ' Ueber radio- 

 aktive Substanzen ' and Karl Hofmann's ' Dis 

 Radioaktiven StofFe nach dem gegenwartigen 

 Stande der Wisseusehaftlicheii Erkenntnis.' 

 Crookes' ' Select Methods ' is classic, but not 

 up to date. Recently the first book on the 

 ' rare earths ' published in America came from 

 the pen of Dr. Ohley, but we are not reviewing 

 that work. One almost wonders why such a 

 book as the one under discussion has not been 

 offered before. It comes at a ripe period and 

 well qualified it is to meet a want. 



The book is exactly what it pretends to be. 

 The different elements are not taken up in 

 the order of the periodic classification, but 

 each one is treated in a systematic manner; 

 a short history of the discovery, occurrence 

 (with names of the minerals and their ac- 

 cepted formulas, with the average percentage 

 of the particular earth indicated), its extrac- 

 tion, preparation, properties, followed by a 



