July 3, 1914] 



SCIENCE 



29 



1 plate; 109 figures in text. Price, 8 Marks. 



During the last fifteen years the older rather 

 tedious and somewhat intricate methods for 

 the calculation and drawing of crystals hare 

 been greatly simplified by the contributions of 

 Goldschmidt, Penfield, Wulff and Hutchinson 

 especially. The purpose of the present text is 

 to bring together these various methods in a 

 clear and concise form in a single treatise. 



The general part of the book comprises 

 sixty-six pages and includes a discussion of 

 the stereographic, gnomonic and linear pro- 

 jections and the development of general for- 

 mulas for the calculation of crystals. The 

 use of the protractors of Hutchinson and Pen- 

 field are described at length, as is also the 

 stereographic net of Wulff. All possible cases 

 of crystal-calculation are then taken up fully 

 in a discussion extending over twenty pages. 



The special part of the text, consisting of 

 sixty-one pages, is devoted (a) to the applica- 

 tion of the methods of crystal-calculation, 

 examples being introduced for each system; 

 and (6) to crystal-drawing. Here the methods 

 for the drawing of crystals directly from ster- 

 eographic and gnomonic projections are 

 given first. These are followed by those in- 

 volving the use of the axial cross for the pro- 

 jection of simple and twinned crystals. 



The treatment throughout the book is con- 

 cise but clear, and illustrated with 109 dia- 

 grams. There is also a bibliography of the 

 most important texts and papers on the subject. 

 The book is a valuable contribution and all 

 advanced students of geometrical crystallog- 

 raphy should have access to it. 



Edward H. Ejjaus 



'MiNERATiOGICAL liABORATOET, 



Univeesity of Michigan 



The Electrical Conductivity and Ionization 

 Constants of Organic Compounds. By 

 Heywaed Scudder, B.A., B.S., M.D. New 

 York, D. Van Nostrand Co. 1914. Pp. 568. 

 Price $3.00. 



In the words of the author, "the object of 

 this book is to present as far as lies in my 

 power a bibliography of aU the measurements 



of the ionization constants and the electrical 

 conductivity literature between the years 1889 

 and 1910 inclusive, together with the values of 

 the ionization constants, and certain values 

 of the electrical conductivity measurements. 

 Qualitative work is also included. . . . Prom 

 1910 to the beginning of 1913, important cor- 

 rections that have come to my notice have 

 been inserted." 



As to arrangement: "The book is divided 

 into a set of tables arranged according to the 

 names of the compounds, containing all the 

 data that may be given with a bibliography 

 of all references to each compound; a formula 

 index to the compounds; a bibliography ar- 

 ranged according to the names of authors; a 

 subject index to certain subjects ; and a journal 

 list giving the names of all journals examined 

 with the number and date of the last volume 

 examined." 



The first set of tables will show the values, 

 if known, of the specific conductivity of the 

 pure substance; the ionization constant; the 

 conductivity in aqueous solution; the conduc- 

 tivity in solvents other than water; the con- 

 ductivity under various eonditionf as to tem- 

 perature and pressure and in various mix- 

 tures; the conductivity of the salts at many 

 different temperatures and in many different 

 solvents. 



The vast amount of labor that the author 

 must have expended upon this compilation 

 will be greatly appreciated by workers in this 

 field of physical chemistry. As the variation 

 in the expression for the dilution law lately 

 suggested by Kraus and Bray is likely to 

 awaken a new interest in conductivity values 

 and ionization constants, the book should prove 

 to be of much service. 



The list of errata is wonderfully small con- 

 sidering the nature of the work. 



E. H. Archibald 



NOTES ON METEOROLOGY AND 



CLIMATOLOGY 



" The Eainf all of California," by Professor 



Alexander McAdie (Univ. Calif. Geogr. Pub., 



Vol. 1, No. 4, pp. 12Y-240, Pis. 21-28). This 



