July 18, 1919] 



SCIENCE 



71 



ing mass are properly timed to bring about 

 the increasing amplitudes. 



The subject is treated analytically in the 

 same journal by A. Hartwich, Vol. 17, 2Y, 

 1914. He arrives at an expression identical 

 with that for Kepler's second law. 



Paul E. Klopsteg 

 , Philadelphia, 

 July 9, 1919 



SCIENTIFIC BOOKS 



Sewage Disposal. By Leonard P. Kinnicutt, 

 late Director Department of Chemistry, and 

 Professor of Sanitary Chemistry in the 

 "Worcester Polytechnic Institute; C.-E. A. 

 "WiNSLOw, Professor of Public Health in the 

 Yale School of Medicine and Curator of 

 Public Health in the American Museum of 

 Natural History, liTew York, and E. Win- 

 THROP Pratt, Consulting Engineer, M.Am. 

 Soc.C.E. Second Edition, rewritten. New 

 York, John Wiley & Sons, Inc. ; London, 

 Chapman's Hall, Ltd. Cloth; 6x9 in. 

 Pp. 547. Illustrated. $4.00. 

 The first edition of this book which was 

 reviewed by the writer in Science, February 

 10, 1911, Volume XXXIII., page 222, has 

 been a successful reference book for students 

 studying the fundamental principles of this 

 branch of municipal sanitation. The present 

 edition has been thoroughly revised and in- 

 creased in size by about one himdred pages. 

 Progress has been rapid during recent years 

 in this branch of the field of municipal sani- 

 tation. The revision of this book is timely as 

 it is generally recognized that activities along 

 this line, retarded by the world war, will 

 shortly be taken up again with renewed vigor. 

 The style of the book is attractive and it is 

 well arranged for use in the class room. 

 Fundamental principles are clearly stated and 

 use is made liberally of practical illustrations 

 drawn from various important documents and 

 investigations not only in this country, but 



removal of suspended solids, with a compre- 

 hensive recital of advantages and disadvan- 

 tages as now understood, and improvements 

 in the fine screening of sewage, and progress 

 in disposal of sewage sludge and the recovery 

 of grease and fertilizing constituents from 

 these waste products. Investigations con- 

 ducted on a comprehensive scale at Cleve- 

 land, Chicago, Milwaukee and New Haven are 

 described with summaries of results, as pub- 

 lished. One of the merits of the book is that 

 it is written from the viewpoints of the engi- 

 neer, the chemist and the bacteriologist, thus 

 bringing out for the consideration of the sani- 

 tarian and student the general principles of 

 the subject from the angles stated, as is nec- 

 essary in order to appreciate the practicability 

 and efficiency of the respective methods. 



The authors deserve commendation for 

 their temperate statements on topics where 

 ciirrent literature shows difi'erences of opinion 

 due presumably to variations in local condi- 

 tions not as yet fully understood. 



Little attempt has been made to set forth 

 completely the most recent results obtained 

 from the operation of plants most lately in- 

 stalled in this country. This may prove dis- 

 appointing to some who devote themselves en- 

 tirely to work in this particular field, but it is 

 probably wise on the part of the authors to 

 base a book for class room use on the broad 

 historic background which as stated in the 

 preface, forms the surest basis for real com- 

 prehension of the general principles of the 

 subject as now understood. Teachers and 

 students of this subject should welcome this 



new volume. _, ttt -n 



George W. Fuller 



In bringing the book up to date, attention 

 has been paid in particular to the activated 

 sludge process, the two-story tank for the 



SPECIAL ARTICLES 



THE POSSIBLE PRESENCE OF CORONIUM IN 

 HELIUM FROM NATURAL GAS 



One of us (Cady), with McFarland,i ob- 

 served a number of lines in the spectra of 

 samples of helium obtained from natural gas 

 which did not belong in the spectra of helium, 



1 Kansas University Geological Survey, ' ' The 

 Composition of Natural Gas," p. 264. 

 ^Proc. Boy. Soc, 67, 467, 1901. 



