SULPHUR. 



Germany, by which the fuming sulphuric acid, 

 which answers so well for dissolving indigo, is 

 obtained. Its colour is always dark, and it is 

 opaque. I do not know the reason of this opa- 

 city, but suspect the presence of some selenium 

 in it, from some phenomena which I have ob- 

 served. The specific gravity of this acid is 1'896. 

 I find it, by a careful analysis, to be a compound 

 of 2 atoms acid, and 1 atom water. Now 



2 atoms acid =10 



1 atom water = 1-125 



11-125 



So that an integrant particle of it weighs 11 '125, 

 and contains 1/1&5 parts water and 10 parts of 

 pure acid. 



4. When this acid is exposed to the air, it 

 smokes, in consequence of its great avidity for 

 moisture. It is much more volatile than the 

 sulphuric acid of this country. When heated in Pure dry 



. -ii i sulphuric 



a glass retort to which a receiver is luted, and add. 

 surrounded with a mixture of snow and salt, one 

 half of the acid passes over in a solid state, form- 

 ing a snow white solid acid, like asbest.us in ap- 

 pearance. What remains in the retort is a com- 

 pound of 1 atom acid and 1 atom water or it is 

 precisely similar to the acid of this country. I 

 have not been able to determine the specific gra- 

 vity of this acid : its avidity for water is so great 



o 4 



