November 21, 1913] 



SCIENCE 



745 



important Appalachian field; by means of it 

 correspondences and contrasts with the de- 

 velopments elsewhere of the Appalachian 

 Devonian trough-seas are made more lucid. 

 The writer feels at liberty to speak thus, as 

 he frankly concedes that his pajt of the book, 

 done ten years ago and laid aside, has been 

 more appropriately attired by the generous 

 labors of Dr. Swartz. 



Though the writer's appearance in Science 

 as reviewer of these volumes is due to the 

 solicitation of its editor, he may take ad- 

 vantage of that fact to express the conviction, 

 which will be shared by all students of the 

 Devonian, that this work is a distinct credit 

 to the science and its accomplishment an 

 added honor to the distinguished head of the 

 Maryland Geological Survey. 



John M. Clarke 



Technical Gas and Fuel Analysis. By Alfred 

 H. White, Professor of Chemical Engineer- 

 ing, University of Michigan. Published by 

 McGraw-Hill Book Company as one of the 

 International Chemical Series. 1913. Pp. 

 255. $2.00 net. 



The book contains seventeen chapters, the 

 "first twelve of which deal with gas analysis, 

 the thirteenth with the analysis of liquid 

 fuels, and the remaining four with the analy- 

 sis of coal. 



The methods described in the chapter on the 

 ■sampling and storage of gases are open to 

 objection in that water is used as the confining 

 liquid. The author carefully emphasizes the 

 :fact that the water to be used must be satu- 

 rated with the gas in question ; but changes in 

 temperature and changes in the composition 

 of the gas are sufficient to change the amounts 

 of the various constituents dissolved in the 

 •confining liquid. Such changes are to be ex- 

 T)ected when the gas sampling extends over an 

 appreciable time interval, and render worth- 

 less the results of the analysis in the case of 

 •certain gas mixtures. There is no objection to 

 using water in sampling gases of low solubility 

 •where extremely accurate results are not re- 

 quired, but such a condition does not fre- 

 quently arise. 



No description is given of the apparatus 

 most commonly employed in technical gas 

 analysis at the present time, i. e., the original 

 Hempel apparatus, the author's modification 

 of both the burette and the pipettes being 

 offered in its place. In the opinion of the re- 

 viewer, the Hempel apparatus deserves a 

 prominent place in any text-book on gas analy- 

 sis because of the simplicity of its manipulation 

 and the rapidity with which results that are 

 sufficiently accurate for most technical pur- 

 poses may be obtained. The slightly greater 

 accuracy obtainable with the White apparatus 

 does not seem to warrant its general use when 

 the longer time and greater inconvenience that 

 are considered. 



In the chapter on methods of explosion 

 and combustion, emphasis should have been 

 laid upon the necessity of employing mercury 

 in the burettes that are used with the explo- 

 sion and combustion pipettes, and in the com- 

 bustion of methane over copper oxide, on ac- 

 count of the solubility in water of the carbon 

 dioxide that is formed. In this connection, 

 the statement on page 57 concerning the com- 

 bustion of methane over copper oxide needs 

 revision : " If the gas had been passed back and 

 forth into a pipette filled with water during 

 the combustion there would have been no 

 change in volume, but since the gas was 

 passed into the caustic pipette during the com- 

 bustion process and the CO, was absorbed the 

 contraction equals the methane." A similar 

 sentence also occurs later on the same page. 



In the discussion (p. 85) on the combustion 

 of hydrogen, the author criticizes the method 

 of Dennis and Hopkins on the basis of the 

 formation of oxides of nitrogen, on what seems 

 to the reviewer insufficient evidence that was 

 published twelve years ago. He seems to have 

 overlooked the results obtained by Ehodes.i 

 These results show that the volume of the 

 oxides of nitrogen that are formed when the 

 combustion is properly performed is always 

 less than .01 c.c, a figure so small as to be 

 negligible. 



The author dismisses the subject of the 

 various improved forms of the Orsat apparatus 

 recently placed on the market with a short 



1 Dennis 'a "Gas Analysis," page 153. 



