October 12, 1905] 



NA TURE 



579 



and even to fire on the riotous crowd. As for the 

 nefjroes, whom the L'nited States have always with 

 them, he suj^'^j^ests onlv the need for training in the 

 simpler arts and handicrafts; for a literary education, 

 in his judgment, they are still wholly unfit. 



PRACTICAL ORGANIC CHEMISTRY. 

 .1 Systematic Course of Practical Organic Chemistry. 

 By Lionel Guy Radcliffe, with the assistance of 

 Frank Sturdy , Sinnatt. Pp. xi + 264. (London: 

 Longmans, Green and Co., 1905.) Price 4$. 6d. 



THIS book is intended mainly for students of 

 i-lcmentary organic chemistry. The students 

 are supposed to work about five hours per week, and, 

 consequently, experiments which take a longer time, 

 rmd must be finished without interruption, are 

 omitted. 



The exercises include a variety of important re- 

 actions and involve work with many of the more 

 common compounds and reagents in organic 

 chemistry. There is a set of e.xercises on the fatty 

 compounds, and another on benzene; these include 

 instructions in the observation of melting point and 

 boiling point, in the determination of specific gravity, 

 of the equivalent of an acid, and of sugar by the use 

 of Fehling's solution. 



This course worked through, there is a higher 

 course, including the preparation of such substances 

 as anisol, benzyl chloride, and benzaldehyde, the de- 

 termination of equivalents and molecular weights, and 

 of carbon, hydrogen, nitrogen, &c. 



.More care might have been spent on the finish of 

 the book. The punctuation has been neglected ; e.g. 

 " recrystallise until the m.p. 's do not change" 

 (p 16), and " recrystallise the hydrobenzamide, 

 formed from hot alcohol " (p. no). The diction is not 

 what it ought to be. " Heated alone succinic acid 

 sublimates " (p. 196). " See if the example obtained 

 [of methyl orange] is sensitive to acids " (p. 96). 



The instructions for experiments are fairly detailed 

 and generally good. Certain mistakes have been 

 made. The student is repeatedly directed, after 

 having dried a preparation by calcium chloride, to 

 distil it in presence of the drying agent (e.g. pp. 54, 

 176). If a dry distillate is desired, the distillation 

 should be carried out after removing the calcium 

 chloride. .Again, in determining inolecular weight by 

 X'ictor Meyer's method, the volume and temperature 

 of the expelled gas may surely be read without wait- 

 ing so long as an hour (p. 120). Is a minute not 

 long enough ? 



L'nder protest, the authors give a section on the 

 qualitative analysis of organic mixtures, " for the 

 sake of students who are taking certain examin- 

 ations." "The authors are quite sensible of the 

 fact that the analysis of such mixtures cannot be re- 

 garded as useful practical organic chemistry " 

 (p. 172). Surely this is an impatient verdict. Quali- 

 tative analysis is a valuable training in so far as 

 the student is led to bring book knowledge to bear 

 on work in the laboratory, and is prevented from 

 taking suspicion for proof. The teacher should re- 

 NO. 1876, VOL. 72] 



quire him, in every case, to produce a specimen (or a 

 derivative) of each constituent of the mixture. With 

 this stipulation,- knowledge, resource and judgment 

 are needed in organic qualitative analysis even more 

 than in inorganic. How many different ways are 

 available for the separation of organic substances from 

 one another: — precipitation, the use of different sol- 

 vents, ordinary and steam distillation, extraction by 

 ether from acid and alkaline solution, hvdrolvsis, 

 oxidation, &-c. ! Surely time spent in mastering these 

 methods of analysis is not wasted. .\. N. .M. 



OUR BOOK SHELF. 

 Die Entwickelung der cleclrischen .Messuiigcu. By 



Dr. O. Frolich. Pp. xii+192; 124 illustrations. 



(Brunswick : Vievveg and Son, 1905.) Price 6 



marks. 

 This is the fifth of a series of scientific monographs 

 published under the general heading Die ]Visseii- 

 schaft. It consists of an historical sketch of the 

 development of physical measurements, especially of 

 those connected with electrotechnics. It must be 

 admitted that in this go-ahead age the technical 

 m.in finds little time to make a retrospect of his sub- 

 ject ; he is too much concerned with its developed 

 aspect. Even in colleges and schools, as the pub- 

 lisher states, the historical side of the subject is too 

 much nedected. The present volume is intended to 

 remove this reproach. 



To give an idea of the book, we will outline here 

 the first chapter (on current measurement). In its 

 first section it deals with the first galvanometer, 

 starting with the work of Oersted and Schweigger 

 on the action of a current on a magnetic needle. 

 Then follow the fundamental laws of constant 

 currents as developed by Ohm, .Ampere, Biot-Savart. 

 and the methods of demonstrating them. The astatic 

 needles of Nobili and Davy and the measurements 

 of Faraday are next described, and this section 

 concludes with the methods devised for calibrating the 

 early types of galvanometer. 



The second section is called the mirror galvano- 

 meter. It describes the work of Gauss and Weber 

 on absolute measurements, the first telegraph of 

 Gauss and Weber (1S33), and the .Atlantic cable 

 furnished with mirror galvanometers by Lord Kelvin 

 (1858). The remainder of the section deals with 

 improvements effected in the control of the moving 

 system (damping, &c.), and describes the galvano- 

 meters of Wiedemann, .Siemens, and Kelvin, and the 

 more recent variants of du Bois and Rubens, 

 Paschen, Hartman and Braun, d'.Arsonval, Edelmann, 

 and Siemens and Halske. 



When it is mentioned that all this is included 

 in thirty pages it will be realised that the descrip- 

 tions are exceedingly brief. The general impression 

 conveyed is that for a book of this kind to be of 

 much use, fuller treatment is necessary. Still, 

 it will serve to direct attention ,to the general trend 

 of advance, and to indicate the names of those that 

 share the chief honour of it. Its value would be 

 considerably increased by a larger number of refer- 

 ences to original sources of information. These are 

 given sometimes onl)-. 



Zoologischer Jahresbericht fiir 1904. Edited by Prof. 



P. Mayer. (Berlin : Friedlander and Son, 1905.) 

 The zoological station at Naples, for which this 

 bulky volume, like its predecessors, is published, is 

 to be congratulated on the early date of its issue and 

 the thoroughness with which the various contributors 



