rEBRUABY 20, 1914] 



SCIENCE 



287 



It is difBenlt to see in a work devoted exclu- 

 sively to gas analysis why nearly a chapter 

 should have been given to the heating value of 

 solid fuel; or why the practically obsolete 

 Honigmann gas burette should be described; 

 or why the method of Drehschmidt-Hempel for 

 total sulphur — which is almost never used in 

 this country — is included. 



One can not help being struck by the way in 

 which reference has been avoided to American 

 apparatus, and to a lesser degree to American 

 work in this field. For example, Fig. 26 is of 

 a German wet gas meter with the information 

 that it can be obtained from Elster of Berlin! 

 This extreme conservatism or love for German 

 a,pparatus leads the author still to use 

 the form of sulphuric acid pipette (p. 24Y) 

 which is slow and may give rise to inaccu- 

 rate results; to employ the expensive and 

 clumsy double absorption pipette (p. 57) which 

 is diificult to fill and empty; to fasten the gas 

 pipettes with plaster of Paris (p. 54) into their 

 fixed iron supports, instead of using screw 

 clamp holders or a wax that can be melted and 

 a movable collar which allows pipettes of 

 almost any dimensions to be employed ; and 

 finally to say (p. 85) that the rubber protect- 

 ing bulbs for the Orsat pipettes are a " draw- 

 back " or " rapidly deteriorate " — -which those 

 of German make certainly do; had he used 

 those of good American manufacture he would 

 have had no trouble. It was shown years ago 

 how all these difficulties could be avoided and 

 experience with hundreds of students has con- 

 firmed the methods then recommended. 



In spite of these defects the book has many 

 excellent features. Chapter ST., on the calcu- 

 lations involved in the combustion of gases, 

 is especially good, as is also the treatment of 

 ozone and carbonic oxide. The chapter on 

 acetylene is very complete. Among new ap- 

 paratus is mentioned the gas refractometer 

 and rotameter, and also some gas absorption 

 bottles; among new methods may be noticed 

 the determination of hydrogen by colloidal 

 palladium and of oxygen by sodium hyposul- 

 phite. The book is particularly valuable in 

 research or to the experienced man. 



A. H. Gill 



Mechanism. By Egbert McArdle Keown,. 



B.S., Assistant Professor of Machine De- 

 sign, University of Wisconsin. 



Professor Keown has attempted in this book 

 to give a brief treatment of the subject of 

 mechanism in such a way as to furnish ma- 

 terial for half a school year's work of six hours 

 per week partly in the class room and partly 

 in the drafting room. The book contains little 

 that is new in the way of subject matter 

 covered and there is much similarity to other 

 and older text-books in the general method of 

 handling certain parts of the subject. The 

 order in which the various mechanisms are 

 considered is radically different from that usu- 

 ally followed and impresses one at first as 

 being rather questionable, although the author 

 seems to have found it satisfactory in his own 

 teaching. 



Chapter I. gives the usual discussions and 

 descriptions of motion, velocity, etc., most of 

 which are well stated. The student is then 

 plunged at once, in Chapters II. to V., into 

 the consideration of link work with all its 

 intricacies, so puzzling to the student whose 

 imagination has not yet been trained suffi- 

 ciently to enable him to readily grasp this 

 rather difficult part of the work. 



Chapter VI. presents a fairly thorough and 

 clear treatment of the subject of cams and is 

 particularly well illustrated with a large num- 

 ber of diagrams and pictorial drawings. 



Chapters VII. and VIII. treat the subject 

 of gearing both for parallel and non-parallel 

 shafts. The treatment is clear, with consider- 

 able practical information and a number of 

 good illustrations. 



Very little attention is given to the impor- 

 tant matter of trains of gears. A short chapter 

 is devoted to connection by means of belts, 

 chains, and ropes, and another short chapter 

 to various mechanisms for giving intermittent 

 motion. The book contains a large number of 

 illustrations, many of which are exceptionally- 

 good. A number of problems are given at the- 

 end of each chapter, adapted both for class 

 room work and for solution on the drawing 

 board. These form a valuable part of the- 

 book. 



W. H. JiMES 



