OF ARTS AND SCIENCES: MARCH 14, 1865. 



475 



Fig. II. 



of lead and asbestos cautiously drawn out into 

 a beaker glass, by means of a bent iron wire, 

 and the tube then inverted within another 

 tube, e e, closed at one end, as shown in Fig. 

 II. The mixture of peroxide of lead and 

 asbestos contained in the beaker glass is now 

 treated with a strong solution of bi-carbonate 

 of soda, and left to stand for about twenty-four 

 hours, with frequent shaking.* 



Solution of bi-cai'bonate of soda is also 

 poured into the tube e e until the level of the 

 liquid shall have reached a point, f, on the 

 combustion-tube, a little above that which was 

 occupied by the plug c, and this is also left 

 to stand as the other. After the lapse of suffi- 

 cient time for the reaction to be completed, 

 the solution is filtered from the asbestos mix- 

 ture, including also the solution in the tube e e, 



and not omitting to carefully rinse out the anterior portion of the com- 

 bustion-tube. The asbestos mixture upon the filter is then thoroughly 

 washed, the filtrate concentrated by evaporation, and the sulphuric acid 

 precipitated with chloride of barium. 



The following results of analyses of bi-sulphide of carbon indicate the 

 degree of accuracy afforded by this process. 



The preparation employed was commercial bi-sulphide of cai'bon, 

 which was first subjected to re-distillation. 



Analysis 1. 0.1414 gramme of bi-sulphide of carbon gave 0.0806 

 of carbonic acid, and 0.8592 of sulphate of baryta. 



Calculated. 



Carbon, C 6 15.79 



Sulphur, 



s. 



32 84.21 



99.31 



100.00 



Analysis 2. 0.274 gramme of the same substance gave 0.158 of 

 carbonic acid, and 1.6768 of sulphate of baryta. 



Calculated. Found. 



Carbon, C 6 15.79 15.73 



Sulphur, S2 32 84.21 84.05 



100.00 



99.78 



* H. Rose, Chimie Analytique, new French edition, p. 662. 



