KICHARDS. — CONCERNING GAS-ANALYSIS. 279 



Summary. 



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

 the simplest apparatus, and yet is capable 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 which 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. 



