SILICON. 197 



1. Berzelius has concluded from his analysis 

 of silicated iron, that the atomic weight of silica 

 is 1-988. But the mean of the experiments of 

 Berzelius and Stromeyer gives us for its atomic 

 weight 1-9966. 



2. The mean of the analysis of eight native 

 silicates of different kinds gives us the atomic 

 weight of silica 2-00245. 



3. My decomposition of carbonate of potash 

 by silica gives for its atomic weight 1 -997^8. 



4<. The analysis of the hydrates of silica gives 

 its atomic weight exactly 2. 



Even if we were to strike a mean from all 

 these different estimations, the weight of an 

 atom of silica would not deviate so much as 

 roVoth part from 2. But this method of pro- 

 ceeding would not be quite proper. The ex- 

 periments on the hydrates being most easily 

 made, and most susceptible of precise results, 

 should have the greater effect in fixing our no- 

 tions on the subject. Now, the hydrates make 

 the atomic weight of silica precisely 2. Next 

 to the hydrates, the greatest confidence seems 

 due to the mean deduced from the analysis of 

 the eight silicates ; now, this mean differs from 

 2 by only yornjth part. Upon the whole I am 

 persuaded, that no unprejudiced person who 

 peruses the preceding details can have any 

 doubt that the true atomic weight of silica is 2. 

 . Silica is a compound of silicon and oxygen. 



N 3 



