RICHARDS. — CONCERNING GAS-ANALYSIS. 279 



Summary. 



In this paper is described a method of gas-analysis which demands only 

 the simplest apparatus, and yet is caj^able of yielding results accurate 

 enough for many ordinary purposes. The limitations of this apparatus 

 are compared with those of other gas-analytical methods. In particular 

 the importance of applying the correction for aqueous vapor in all meth- 

 ods whicli depend upon the measurement of changing pressure in constant 

 volume is emphasized. 



It is worthy of remark that this simple method forms a highly instruc- 

 tive exercise in gas-analysis for a class of students in this subject. 



Cambridge, Mass., U, S. A. 

 May 31, 1902. 



