DR. TURNER ON CHLORIDE OF BARIUM. 



297 



chloride yield only 1 1 1.32 parts of sulphate of baryta. It is proper to state, in 

 reference to the foregoing experiments, that traces of chloride of barium 

 are apt to adhere to the sulphate of baryta ; but this source of error is easily 

 avoided by decanting the supernatant fluid after subsidence, and stirring the 

 precipitate with hot water acidulated with sulphuric acid. 



In order to determine the chlorine of chloride of barium by means of silver, 

 it was desirable to ascertain the composition of hornsilver. For this purpose 

 some fine silver containing only traces of gold and copper was dissolved in 

 nitric acid, precipitated by sea-salt, digested in dilute nitro-muriatic acid, and 

 washed. The dry chloride was then reduced by means of carbonate of potash 

 in the usual manner, and after throwing a few fragments of nitre upon the 

 fused metal, it was granulated and then boiled repeatedly in distilled water. 

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

 other impurity ; whereas it is difficult in employing 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 dissolved in nitric 

 acid, and precipitated by muriate of baryta in excess. The precipitate after 

 being carefully washed and collected on a double filter, yielded 4 1 .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 dissolved as usual, pre- 

 cipitated 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 



MDCCCXXIX. 2 Q 



