824 



SCIENCE. 



[N.S. Vol. XI. No. 282. 



beginners. A student with some knowledge of 

 organic chemistry could use it as a text-book if 

 it were possible for him to resolutely confine his 

 attention to the ' coarse print.' But it is as a 

 reference book for the student who wishes to re- 

 fresh his memory not merely of one compound, 

 but of the complete chemistry of a group of 

 compounds, that the work is of peculiar value, 

 and may be cordially recommended. 



Edwaed Kenouf. 



Optical Activity and Chemical Composition. By 

 Dr. H. Landolt, Professor of Chemistry in 

 the University of Berlin. Translated, with 

 the author's permission, by John McCeae, 

 Ph.D. Whittaker and Co., London, and the 

 Macmillan Co., 66 Fifth Ave., New York. 

 1899. Small 8vo. Pp. 158. Price, $1.00. 

 This little book forms a translation of the 

 eighth chapter of the first volume of Graham- 

 Otto's ' Lehrbuch der Chemie ' and is a smaller 

 and condensed edition of the author's well- 

 known ' Dasoptische Drehuugsvermogen organ- 

 ischer Substanzen und dessen praktische An- 

 wendungen,' published in 1898. The subject 

 is treated under three heads : I. General 

 Principles of Optical Activity ; II. Connection 

 between the Rotatory Power and the Chemical 

 Composition of Carbon Compounds, and III. 

 Connection between Degree of Kotation and 

 Chemical Constitution. Under the first head 

 are discussed such subjects as crystal rotation, 

 liquid rotation, molecular rotation, measure- 

 ment of rotation, specific rotation, variations 

 of specific rotation with concentration and 

 change of rotatory power of dissolved sub- 

 stances with time, multirotation. Under the 

 second head are treated optical modifications, 

 the investigations of Pasteur, the van't HoiF 

 and Le Bel theory, calculation of the number 

 of optically active isomers of a compound from 

 the number of asymmetric carbon atoms which 

 it contains, the formation and properties of 

 racemic compounds, resolution of racemic 

 substances into the antipodes, formation and 

 properties of the active modifications, trans- 

 formation of one antipode into the other, the 

 configurationally inactive non-decomposable 

 modifications and their differences from racemic 

 inactive isomers. Under the third head are 



taken up isomeric compounds, including stereo- 

 isomers, homologous series, influence of the 

 mode of linkage of the carbon atoms, summa- 

 tion of the rotatory actions of several asym- 

 metric groups, optical superposition and the 

 dependence of the rotatory power of an active 

 atomic grouping on the masses of the four rad- 

 icles united to the asymmetric carbon atom, the 

 hypothesis of Guye. 



The translation is well done and the subject 

 is brought up to date by notes and additions by 

 the translator. The subject is presented in a 

 very attractive and readable form and the book 

 can be heartily recommended to anyone, who 

 desires to know the present state of our knowl- 

 edge regarding the relation existing between 

 optical activity and chemical composition ; 

 though for more detailed information Landolt's 

 ' Das optische Drehuugsvermogen organischer 

 Substanzen und dessen praktische Anwendung- 

 en ' must be used. 



W. E. Oendoeff. 



SCIENTIFIC JOURNALS AND ARTICLES. 



The Osprey for April, a little belated, opens 

 with the fourth part of 'Birds of the Road,' by 

 Paul Bartsch. "Wm. L. Wells describes the 

 'Nesting of some Rare Birds,' including the 

 yellow rail and solitary sandpiper, and Theo- 

 dore Gill presents the second part of ' William 

 Swainson and his Times ' which carries Swain- 

 son through his journey to Brazil. In editorial 

 comments under ' Birds and Women ' the situ- 

 ation is summed up in a few words " If the de- 

 mand exists for anything, that demand will be 

 supplied if it can be done with a profit. ' ' Under 

 Notes is to be found an extraordinary account 

 of ' How Two Lions stopped an African Rail- 

 road,' and other matters of interest. 



A Bulletin of Mathematics and of the Physical 

 and Natural Sciences, to be published semi- 

 monthly in the interest of teachers in Italian 

 schools, has been established by Professor 

 Alberto Conti, of Bologne. 



SOCIETIES AND ACADEMIES. 

 GEOLOGICAL SOCIETY OF WASHINGTON. 



The 101st meeting of the Society was held at 

 the Cosmos Club April 11, 1900. 



