156 ~=—- Friedel and Crafts on the Ethers of Silicic Acid. 
It is not our intention to enter into the history of the discus- 
sion of the true atomic weight of silicium; but it will perhaps 
be useful to recall some of its principal phases. In the memo- 
SiO, for the chlorid of silicium and for silicic acid. At the 
same time he noticed the analogy between silicic and carbonic 
acids. These ideas do not appear to have attracted the attention 
they merited, because they were too far in advance of those re- 
ceived at the time, and those who have since taken them up 
— doubtless been unintentionally unjust in not quoting their 
author. : 
Ebelmen employed the atomic weight for silicium as estab- 
lished by Dumas, and wrote the formula of silicic ether, 
SiO, C,H, 0, (Sic 7, O—8, C—6, H=1). 
This is the most simple expression for the result of his analysis, 
but his formula is not in accordance with that of Dumas for 
silicic acid; for in order to correspond with it, silicic ether should 
* ai ‘a Théorie 
+ Ann. de Chim, et Phys., [2], xxxiii, 367; 1826. : 
¢ Ann. de Chim. et Phys., [2], lii, 113; 18338. We will add that in this memoir 
Mr. Gaudin gives the d tion of atom and molecule which is received at the ea, 
ent da ; happy in being able to render justice to an acute inte: ect, 
whose penetration has not been sufficiently recognized. 
i Ann. de Chim. et Phys. [3], xvi, 141; 1846. 
Handbuch der Chemie, ii, 339; Heidelberg, 1844. 
des pa Chimiques, p. 134; Paris, 1819. 
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