186 Dr. Turner on the Composition of Chloride of Barium. 



In the silver thus prepared I could not detect potash, gold, 

 copper, or any other impurity; whereas it is difficult, in employ- 

 ing common silver, to purify it completely by one operation. 



1. Of this silver 28*407 grains were dissolved in pure nitric, 

 and precipitated by pure muriatic acid, both of which had 

 been prepared with the greatest care. The whole mass was 

 evaporated to dryness, and yielded 37*737 grains of fused 

 chloride of silver. 



2. In a second similar experiment 41*917 grains of silver 

 yielded 55*678 grains of hornsilver. 



3. In a third, 40*006 grains of silver yielded 53*143 of 

 hornsilver. 



According to the first and third experiments 100 parts of 

 silver correspond to 132*84, and according to the second to 

 132*83 parts of hornsilver. 



4. In a fourth experiment, 30*922 grains of silver were dis- 

 solved in nitric acid, and precipitated by muriate of baryta in 

 excess. The precipitate after being carefully washed and col- 

 lected on a double filter, yielded 41*07 grains of fused chloride; 

 and hence the silver and chloride are in the ratio of 100 to 

 132*82. 



5. In a fifth experiment, 42*255 grains of silver were dis- 

 solved as usual, precipitated by an excess of muriatic acid, 

 and collected on a double filter. The fused chloride amounted 

 to 56*09 grains, giving the proportion of 100 to 132*74. When 

 the silver is thus precipitated by free muriatic acid, and the 

 chloride collected on a filter, the result is constantly below that 

 obtained by the other methods, owing to a trace of the chlo- 

 ride being dissolved by the strong acid solution. 



It may be inferred, as a mean of the four first experiments, 

 that 100 parts of silver correspond to 132*83 parts of chloride 

 of silver. The proportion stated by Berzelius is 100 to 132*75; 

 and it is estimated at 100 to 132*72 by Dr. Thomson. All 

 these results, therefore, are closely correspondent. 



From one of the experiments (No. 4.) just mentioned, it is 

 manifest that the precipitation of chloride of barium by nitrate 

 of silver does not involve any appreciable source of error. To 

 be quite certain, however, as to this fact, chloride of barium 

 was mixed with nitrate of silver in excess, and the precipitate 

 carefully washed. It was then boiled in distilled water, and 

 the fluid examined for silver and baryta; but not a trace 

 of either could be detected. It dissolved completely in am- 

 monia, and the addition of sulphuric acid did not cause the 

 slightest turbidity. 



In five analyses made by precipitating chloride of barium 

 by an excess of nitrate of silver, I obtained the following 

 proportions. 



Chlorite 



