268 FIXED ALKALIES AND ALKALINE EARTHS. 



Sulphuric acid 5 

 Barytes 9- 7 5 



14-75 



From which it is obvious, that 9'7<5 must be the 

 atomic weight of barytes ; but a few additional 

 observations may be requisite to prevent any ob- 

 scurity from incommoding the progress of the 

 reader. 



** When a current of chlorine gas is made to 

 p ass over red hot barytes, this gas is absorbed, 

 while at the same time oxygen gas is evolved 

 and the barytes is changed into chloride of bari- 

 um. Sir H. Davy, to whom we owe this experi- 

 ment, ascertained, that for every volume of chlo- 

 rine gas absorbed by the barytes, half a volume 

 of oxygen gas was evolved. It is obvious that 

 the oxygen gas was displaced from the barytes 

 by the chlorine, and of consequence, the barytes 

 was converted into barium. Half a volume of 

 oxygen gas and a whole volume of chlorine gas, 

 being each equivalent to an atom, it is clear that 

 barytes must be a compound of 1 atom barium 

 and 1 atom oxygen ; consequently, an atom of 

 barium weighs 8 '75. 



%. Muriatic acid was shown, in a preceding 

 chapter, to be a compound of 1 atom of chlo- 

 rine = 4%5 ; and 1 atom of hydrogen = O1&5 ; 

 so that its atomic weight is 4 f 6&5. 



3. Water was likewise shown to be a com- 



