52 Journal of the Mitchell Society. [March 



chine test, which shows one part in a million. Silver nitrate 

 solution was made by dissolving- pure silver prepared accord- 

 ing to the method of Stas by Venable, in pure nitric acid. A 



N 

 solution of — — NaCl was made for determining the chlorine. 



Several series of experiments were carried out to determine 

 the effect of an excess of silver nitrate in solution, of acidity, 

 and of temperature. The temperature was varied from boil- 

 ing - to room temperature (about 23°C). 



One cubic centimeter should have precipitated 0.0143 gm. 

 of Ag-Cl. The following- are some of the results. 



10. AgCl found, 0.756, theoretical, 0.1716; Temp. 30; excess 



N 

 of AgNO s 0.1028; acidity, 18.5 cc. — acid. 



12. AgCl found 0.1732, Temp. 30; excess AgN0 3 0.2399; 



X 

 acidity, 20.4cc. — - acid. 



14. AgCl found 0.1800, Temp. 78; excess AgN0 3 0.2183; 



N 



acidity 25. 6cc. —acid. 



18. AgCl found 0.1754, Temp. 60; excess Ag-N0 3 0.0171; 



. . N 



acidity 25. 6cc. —acid. 



There were twenty-five determinations carried out, all giv- 

 ing too hig-h results, as maybe seen from the fignres given. 

 By another series of experiments carried out at thirty degrees 

 with rapid filtration, it was found that the results in general 

 agreed with the theoretical. But the conditions were very 

 hard to attain. 



We now returned to our thorium and made a series of exper- 

 iments to determine the chlorine of the tetrachloride. But 

 the results were not concordant, which fact was explained by 

 finding that even aldehyde-free alcohol decomposes silver 

 nitrate, causing- finely divided silver to deposit. Of course 

 this method was immediately abandoned. 



Now once again we turned our attention to determining- the 



