466 



SCIENCE 



[N. S. Vol. XLI. No. 1056 



" the latent Heat of steam formation " is given 

 as 967, instead of 970.4. On page 154, the 

 method given for the determination of mois- 

 ture and volatile carbon in coal could be re- 

 placed by standard ones. On page 155, the 

 author states that, from the data of the proxi- 

 mate analysis, " the calorific power of the 

 coal can be approximately calculated by Le- 

 noble's formula " which he gives. A descrip- 

 tion and instruction in the use of a standard 

 calorimeter at this point would not be amiss. 

 On page 158, under " Water," the direction is 

 to dry total solids and the residue, before 

 driving off organic and volatile matter, at 130 

 degrees Centigrade to constant weight, in- 

 stead of at 103 degrees for one half hour. On 

 page 162, the soap method for hardness is 

 given, but no mention is made of the titration 

 methods. 



In the chapters on analytical control in cane- 

 sugar factories, beet-sugar factories and re- 

 fineries, the author tabulates the work involv- 

 ing control of sugar materials and products, 

 indicating what determinations are necessary 

 on each. He avoids repetition as much as pos- 

 sible by referring to the directions for analyt- 

 ical methods given in the chapters devoted to 

 outlines and discussions. One would call 

 attention to the direction for determination 

 of sucrose in molasses, on page 181. Under 

 Clerget, on this page the following is given : 

 " The direct polarization and the polarization 

 after inversion should be carried out on por- 

 tions of one and the same solution; for this 

 reason two or three times the normal weight 

 of molasses should be dissolved in 500 c.c. of 

 water. The determination is then carried out 

 as previously directed." Doubtless he intends 

 that the dilution should be to 500 c.c. instead 

 of " dissolved in." Since in giving the method 

 of Clerget on pages 71 and 178-179, it is 

 stated that the use of subacetate of lead is 

 not permissible, but if a decolorant must be 

 used specially prepared blood-carbon or bone- 

 black should be employed, the operator or stu- 

 dent would refer to these directions when pre- 

 paring his solution for the double polarization 

 of iQolasses, thereby omitting clarification 

 with lead compounds and subsequent delead- 

 ing but resorting to decolorization with bone- 



black or blood-carbon, unless he per- 

 chance referred to the Meissel-Hertzfeld 

 method as given in chapter 6, page 94, which 

 he is hardly expected to do since this method 

 is given and discussed in the chapter given to 

 the determination of sucrose by optical and 

 chemical methods and not to the determination 

 by optical methods as Clerget calls for. Evi- 

 dently the author would not recommend 

 clarification of molasses with subacetate of 

 lead when determining sucrose by the Clerget 

 method. 



Chapter 12 is an invaluable addition to the 

 volume, as a resume of the work of the Inter- 

 national Commission is here given, which is 

 not always at the hands of the chemist, either 

 in the original transactions or in compilation. 

 It is commendable that this so-important work 

 is compiled and condensed in an available 

 form. 



The tables given are well selected and will 

 meet the needs of the sugar analyst, except 

 table 18 (that used in calculating the percent- 

 age of commercial sugar recovered from the 

 sucrose in the massecuite as given by I. H. 

 Morse), which is incomplete and would be of 

 little service except in refineries. 



The subject-matter of the volume is well 

 correlated, repetitions are few, and the style 

 and appearance of the book are good. Although 

 criticism is here brought of some of the meth- 

 ods of analysis, as given in chapter 8, and 

 attention called to the method for the prepara- 

 tion of the solutions in the determination of 

 sucrose in molasses, and to the incompleteness 

 of table 18, this work will be an addition to 

 any technical library and of aid to the analyst 

 experimenter and student, when working on 

 commercial sugars and allied products and fol- 

 lowing routine analytical work in sugar houses 

 and refineries. 



C. S. Williamson, Jr. 



TULANE University op Louisiana 



Electric Arc Phenomena. By Ewald Rasch. 

 Translated from the German by K. Torn- 

 BERG. New York, D. Van Nostrand Com- 

 pany. 1913. Pp. 194. 

 The introduction contains a discussion of 



the relative merits of the electromagnetic and 



