Decembeb 11, 1908] 



SCIENCE 



843 



pressed in two terms, is employed as the form 

 of reduction, to the meridian. 



The major term, depending upon the second 

 power of the hour-angle, has been tabulated 

 by the author for each degree of latitude up 

 to 65° and from degree to degree of declina- 

 tion for each two minutes of hour-angle up 

 to sixty minutes or to such lesser extent as 

 marks the limit at which the minor term of 

 the reduction amounts to less than 45". 



The second or minor term of the reduction, 

 depending upon the fourth power of the hour- 

 angle, is expressed in the form of a diagram, 

 from which the numerical value of this part 

 of the reduction may be readily determined. 



As the intervals between the arguments of 

 the tabulation of the major term are such 

 that in general the tables must be entered 

 with the approximate latitude and the ap- 

 proximate declination and the approximate 

 hour-angle, convenient auxiliary tables have 

 been supplied for taking account of the effect 

 upon the result of differences between the 

 exact values and the tabular values of the 

 data. Various other diagrams and tables, 

 providing for the identification of stars, facili- 

 tating the solution of the equation of equal 

 altitudes, and reducing measured altitudes to 

 true altitudes are also presented to contribute 

 to the completeness of the work. 



A navigator who makes this book one of his 

 possessions and utilizes the information con- 

 tained in it will be repaid many times through 

 the practical benefits that he will derive from 

 it in his daily work. G. W. Littlehales 



Chemische Krystallographie. By P. voN 

 Geoth. Vol. 2. Pp. viii -f 914, 522 figures, 

 8vo, cloth, 32 marks. Leipzig, Wilhehn 

 Engebnann. 1908. (Volumes 3 and 4 are 

 in preparation.) 



Two years ago the first volume of this very 

 important work by Professor P. von Groth 

 appeared. Since then the volume has proved 

 of such great assistance to all interested in 

 crystallized substances, but more especially to 

 the chemical crystallographer, that the second 

 volume, which was promised over a year ago, 

 has been eagerly awaited. A review of Vol- 



ume 1 may be found on pages 143 and 144, 

 Vol. X5V., of Science. 



In Volume 2 the inorganic oxy- and sulfo- 

 salts are discussed. The arrangement of the 

 first volume is retained throughout. This con- 

 sists of placing together all compounds of 

 similar chemical composition and prefacing 

 each group with a critical resume of the work 

 done upon the same, so that one can see at 

 a glance what gaps exist and also along what 

 lines further research may be necessary. This 

 feature alone makes the work invaluable. The 

 descriptions of the individual members of the 

 group, which then follow, furnish all the data 

 extant which are of use or interest to the 

 chemical crystallographer. This volume is in 

 every respect up to the high standard set by 

 Volume 1. It is hoped that the remaining 

 volumes, 3 and 4, may follow in rapid suc- 

 cession. 



Edward H. Kraus 



MlNEEALOGICAX LaBOKATOET, 

 UNrVEESITT OF MICHIGAN 



House Painting, Glazing, Paper Hanging and 

 White-washing. A book for the house- 

 holder. By Alvah Horton Sabin, M.S. 

 8vo, cloth, pp. 121. New York, John Wiley 

 & Sons. 1908. 



This is a thoroughly reliable, readable book, 

 dealing with the subjects of exterior and in- 

 terior painting, varnishing, papering, kalso- 

 mining, white-washing and the painting of 

 structural metal. Technical terms and long- 

 winded descriptions are avoided, and the book 

 should be read by every house user and owned 

 by every house owner. The author's state- 

 ment to the effect that " the talk about people 

 being poisoned by arsenic in wall paper is non- 

 sense," is unfortunate, as the reviewer knows 

 certainly of one ease proved to be due to this 

 cause. A. H. Gill 



Modern Pigments and their Vehicles, their 

 Properties and Uses, considered mainly 

 from the practical side. By Frederick 

 Maire. 8vo, cloth, pp. 266. New York, 

 John Wiley & Sons. 1908. 

 This is a most excellent book written by one 



who evidently knows the practical side thor- 



