THE SYNTHESIS OF ARGENTIC CHLORIDE. 6$ 



experimenters (Dr. Baxter having very kindly given us a piece of his 

 purest silver used in the determination of the atomic weight of iodine, 

 and each of the authors having made separate samples) and two entirely 

 different methods of synthesis. 



Of these methods of synthesis one has already been described, 

 namely, the usual method of solution of the silver in nitric acid, pre- 

 cipitation by hydrochloric acid, and filtration on a Gooch perforated 

 crucible. Of course all the precautions and corrections already dis- 

 cussed were applied with as much care as possible. All the vessels 

 used were afterwards washed with a little ammonia, and the washings 

 tested nephelometrically in order to be sure that no silver was lost by 

 adsorption on the vessels. By this method Experiments 69, 77, 78, 

 80, 81, R. 2, and R. 3 were made. Further unvaried repetition of this 

 process seemed to promise no further light on the question. 



Although this method seemed to leave little or nothing to be de- 

 sired as regards accuracy, it was nevertheless deemed advisable to test 

 it by making a few syntheses by means of entirely a different process, 

 in which all the vessels coming in contact with the precipitate could 

 be weighed. Accordingly a new method was devised, a modification 

 of one of those used by Stas, employing quartz vessels instead of 

 glass. A quartz dish was accurately weighed by substitution of a 

 counterpoise of a similar composition, surface area, and weight. A 

 watch-glass to serve as its cover was weighed in a similar fashion sep- 

 arately. A weighed piece of silver was placed in the dish, which was 

 supported in a large empty "desiccator," whose bottom and sides 

 were well moistened with pure water. The silver was covered with 

 redistilled nitric acid of the usual strength and left covered both by 

 watch-glass and desiccator lid to dissolve slowly over night in a warm 

 place. On the next day the moisture on the glass cover was washed, 

 with great care to avoid the slightest spattering, into the quartz dish. 

 If any spattering occurred it was caught in the large desiccator, which, 

 having been tightly covered, served also to catchall spray proceeding 

 from the solution of the silver. In two experiments, the silver recovered 

 from the water in the desiccator amounted to only 0.02 milligram 

 when estimated by the nephelometer, and in one no silver at all was 

 found in the desiccator. 



Hydrochloric acid gas was next allowed to play upon the surface 

 of the silver nitrate solution in the quartz dish, and the resulting 

 chloride was caused to sink to the bottom by means of a very small 

 glass stirrer, afterwards carefully rinsed. The remaining solution of 



