CHEMICAL CONSTITUTION OF BLEACHING-POWDER. 265 



XXXIII. An Improved Method for preparing Marsh-gas. 

 By C. Schorlemmer, F.R.S. 



Read November 18th, 1873. 



Every one who ever had to prepare soda-lime knows that 

 the preparation of this substance is a troublesome as well 

 as a laborious process. Chemists will therefore hail with 

 pleasure a paper "On the Determination of Nitrogen/' 

 by S. W. Johnson (Liebig's 'Ann.' vol. clxix. p. 69). He 

 has found that, in using the method of Varrentrapp and 

 Will, soda-lime may be replaced by an intimate mixture 

 of about equal weights of anhydrous sodium carbonate 

 and dry slaked lime. It occurred to me that such a mix- 

 ture might also be employed instead of soda-lime in the 

 preparation of marsh-gas ; and I found that by heating an 

 intimate mixture of anhydrous sodium acetate with more 

 than twice its weight of lime and sodium carbonate, a 

 very regular and quiet evolution of marsh- gas took place. 

 The gas thus obtained always contains some acetone, 

 which is easily removed by shaking it with water or, 

 better still, with a solution of acid sodium sulphite. 



XXXIV. The Chemical Constitution of Bleaching -powder* 

 By C. Schorlemmer, F.R.S. 



Read December 2nd, 1873. 



In his classical research " On the Compounds of Chlorine 

 with Bases"* Gay-Lussac has shown that the bleaching 



* Compt. Rend. vol. xiv. p. 927, 

 SER. III. VOL V. T 



