470 



dilute solution of tartaric acid. This acid was placed in a 

 tall flint-glass bottle with narrow neck, the mouth of which 

 was closed (but not air tight) by a cork which was perforated 

 so to receive the vertical arm of the bent tube. Upon con- 

 tact of the chlorine and ore considerable heat was developed. 

 When, the current of gas being still maintained, this began 

 to subside, a lighted spirit lamp with circular wick was 

 placed beneath the ball, and its flame gradually augmented 

 so as to expel the chlorides of sulphur and antimony, and 

 finally to fuse the chloride of lead ; and a smaller spirit 

 flame was at the same time made to play on the tube beyond 

 the ball, so as to cause the volatile chlorides to pass into the 

 tartaric acid, or at least into the vertical portion of the tube 

 whose further extremity was immersed in the acid solution. 

 The tube was now nicked with a file, and broken across 

 at its point of flexure ; and the portion not connected 

 with the ball was subjected to a stream of distilled water, 

 so as to wash any chlorides which it might include into the 

 bottle containing the tartaric acid. This portion of the 

 tube was now heated to redness, so as to render it perfectly 

 dry, and then weighed along with the remaining fragment on 

 which the ball was blown, and which contained the chloride 

 of lead. The weight of this chloride was thus obtained ; 

 being obviously equal to the weight last obtained, diminished 

 by the weight of the ball and tube. It was thus found to 

 amount to 40*96 grains, equivalent to 30*52 of metalHc lead. 

 The remaining constituents of the ore were now in the tar- 

 taric acid, the sulphur being partly in the free state, but 

 chiefly in the form of sulphuric acid. The free sulphur was 

 first separated, and found to weigh 0*1 grain. To the acid 

 solution chloride of barium was added, which threw down 

 the sulphuric acid in the form of sulphate of barytes. This, 

 when well washed, dried, and ignited, weighed 51*87 grains, 

 equivalent to 7*15 sulphur ; hence 7*15 + 0*10 =: 7*25 is the 

 total amount of the sulphur. 



