OCTOBEB 29, 1900] 



SCIENCE 



599 



After 8 :00 a.m. eye-readings were secured 

 ■which show that this is by far the largest 

 storm which has occurred since the records of 

 this observatory began, in April, 1901. The 

 following table will give a general idea of the 

 magnitude of the disturbance. 



It will be seen that there was an observed 

 range in declination of nearly 5° and in 

 horizontal intensity of 1,156 gammas and an 

 •estimated range of over 2,400 gammas, about 

 one eighth of the horizontal intensity. For 

 ■comparison, it may be stated that in the storm 

 -of October 30-31, 1903, which was the largest 

 recorded at Cheltenham before this one, the 

 Tange in declination was 1° 37' and in hori- 

 zontal intensity about 500 gammas. 



J. E. BURBANK 



Coast and Geodetic Subvet 



Magnetic Obseevatoby, 



Cheltenham, :Md. 



SCIENTIFIG BOOKS 



SOME RECENT BOOKS ON CHEMISTRY 



Of the making of text-books there is no 

 end; this season brings an abundant crop. 

 Of those to be considered in this review two 

 are text-books of inorganic chemistry. 



Any book written by Professor HoUeman 

 repays close study. The English translation 

 of his " Text-book of Inorganic Chemistry '" 

 is well known in this country. It is inorganic 

 chemistry for advanced students written from 

 a physical-chemical standpoint. Some of the 

 best known modern text-books seem mainly 

 ■concerned with electrolytic dissociation and 

 the phase rule, banish the periodic system to 

 a page or two at the end of the book and — 

 like nearly all our older books — practically 

 ignore thermo-chemistry. As most French 

 books practically ignore everything but ther- 

 mo-chemistry, it follows that many students 

 ■can not read a French book on chemistry in- 



' " A Text-book of Inorganic Chemistry," by 

 Dr. A. F. Holleman, Professor Ordinarius in the 

 University of Amsterdam. Issued in English in 

 ■cooperation with Hermon Charles Cooper. Third 

 English edition, partly rewritten. New York, 

 John Wiley and Sons, 1908. 



telligently. Professor Holleman gives due 

 space to electrolytic dissociation, phase rule 

 and thermo-chemistry, retains the periodic 

 system and applies them all in the text. A 

 student trained by this book can intelligently 

 read any of the present methods of inter- 

 preting chemical phenomena. The preface to 

 this edition says : 



The portions on the phase rule, spectroscopy, 

 radioactivity, iron-carbon system and metal-am- 

 monia compounds have been largely rewritten by 

 the author, and the chapters on colloids, experi- 

 mental determination of equivalent weights and 

 unity of matter are entirely new. Professor 

 Werner has kindly approved the chapter on metal 

 ammonia compounds. 



Teachers who do not care to use so advanced 

 a book in their classes will find it invaluable 

 for study and reference. 



What has been said of the plan of Ilolle- 

 man's book applies also to the " General 

 Chemistry " of Professor Alexander Smith.' 

 It is a broad comprehensive book written in a 

 catholic spirit on the same general lines as 

 that of Holleman. It is somewhat simpler 

 than the latter and better fitted for the Amer- 

 ican student in arrangement. The book is so 

 well known that it needs no further comment 

 here ; its friends will be glad to see that it has 

 appeared in German with an appreciative in- 

 troduction by Professor Haber. 



Of the other books to be considered in this 

 review five are about inorganic preparations 

 and two are manuals of qualitative analysis. 

 These numbers are significant, indicating a 

 general change in methods of laboratory in- 

 struction. Making inorganic preparations was 

 an important part of the work in the labora- 

 tories of Woliler, Bunsen and the other great 

 teachers of that time. With the increase of 

 interest in organic work, inorganic prepara- 

 tions were neglected more and more till twenty 



- •' Einfiihrung in die allgemeine und anorgan- 

 ische Chemie auf elementarer Grundlage," von Dr. 

 Alexander Smith, Professor der Cliemie an der 

 Universitat Chicago. Unter Slitwirkung des 

 Verfassers iibersetzt und bearbcitet von Dr. Ernst 

 Stern. Mit einem Vorwort von Professor Fritz 

 Haber. Karlsrulie i. B., G. Braun. 1909. 



