276 Berzelius^s Experiments to determine the Composition [Apru,, 



colour of rhuharh ; but this precipitate, when boiled in highly 

 concentrated muriatic acid, is not wholly soluble in that acid ; 

 and when the excess of acid has been driven off", and distilled 

 water added, no precipitate is afforded to carbonate of ammonia. 

 Zinc throws down from it a dark precipitate, which has not the 

 characters of Cadmium. Hence I conclude that it does not. 

 contain Cadmium ; and that the orange-coloured precipitates 

 afforded by sulphuretted hydrogen from the solutions of the ores 

 of zinc are not of themselves indications of the presence of that 

 metal, wanting the subsequent proof of its presence to which 1 

 have alluded ; and the further testimony from subsequent tests 

 used in the examination of the carbonate ; as described in the 

 foregoing experiments. 



I have the honour to be, dear Sir, &c. Sec. 



E. D, Clarke. 



Article VI. 



Experiments to determine the Composition of diff'erent inorganic. 

 Bodies which serve as a Basis to the Calculations relative to the 

 Theor If of Chemical Proportions. By J. Berzelius. 



{Continued from p. 98.) 



Barytes, Sulphate, and Muriate of Barytes. 



Ten grammes of pure muriate of barytes perfectly deprived of 

 water were dissolved in water, and the solution was mixed with 

 nitrate of silver as long as any precipitate fell. I obtained in one 

 experiment 13-806, and in another, 13-808 grammes of fused 

 muriate of silver. Muriate of barytes, therefore, is composed of 



Muriatic acid 26-37 100-000 



Barytes 73-63 279-226 



If we calculate from this experiment the composition of 

 barytes, we find that it must contain 10-45, per cent, of oxygen. 



Ten grammes of muriate of barytes decomposed by sulphuric 

 acid yielded in one experiment 11-217, and in another 11-218 

 grammes of sulphate of barytes. Hence sulphate of barytes i* 

 composed of 



Sulphuric acid 34-337 100-00 



Barytes 65-643 191-07 



If we calculate the composition of barytes from these data, 

 •we find that it should contain 10*443 per cent, of oxygen. The 

 results of these two experiments then only differ 0-00008, and 

 may consequently be considered as vety near the truth. 



