8 



RESEARCHES UPON ATOMIC WEIGHTS. 



gas was further dried by passing through a tube containing resublimed phos- 

 phorus pentoxide. This tube is not shown in the diagram since it was elim- 

 inated in the final series of experiments. 



Nitrogen was prepared by Wanklyn's method of passing air through concen- 

 trated ammonia solution in the bottle M and then over hot copper gauze in the 

 hard glass tube N. The excess of ammonia was removed by dilute sulphuric 



c*=< 



Fig. I. — Apparatus for the fusion of chlorides in a current of hydrochloric-acid gas. 



acid in the bottles and P, and the nitrogen was purified and dried by means 

 of beads saturated with silver-nitrate solution in the tower Q, solid potassium 

 hydroxide in the tower R, concentrated sulphuric acid in the towers S, T, and 

 U, and resublimed phosphorus pentoxide in the tube L. 



Air was purified and dried by reagents similar to those used in the purifica- 

 tion of the nitrogen, in the towers G, H, I, J, K. 



The hydrochloric-acid apparatus was constructed wholly of glass with either 

 ground or fused joints, while the nitrogen and air purifying trains had short 

 rubber connections only at the beginning. Glass gridifons at suitable points 

 gave sufficient flexibility to the apparatus. Ground joints were made tight 

 by means of either concentrated sulphuric acid or with syrupy phosphoric 

 acid. 



A portion of the cadmium ammonium chloride, contained in a weighed plat- 

 inum boat in the hard-glass tube W, was heated gradually to fusion in a current 

 of hydrochloric-acid gas and was kept fused until all the ammonium chloride 



