30 PROCEEDINGS OP THE AMERICAN ACADEMY 



without the formation of silicic acid at the same time. That the 

 soluble product was principally fluosilicic acid is proved by the fact 

 that it gave a precipitate with potassic chloride. 



Tridimethylan iline Disilicotetr a fluoride, ( C c IT N ( C H„) 2 ) 3 ( Si F 4 ) 2 . — 

 Fluoride of silicon has no action ou dimethylaniline alone, but, if the 

 gas is passed through a solution of dimethylaniline in benzol, a floccu- 

 lent precipitate is formed, which is gradually converted into a gummy 

 mass that crystallizes on standing. The crystals were purified by 

 washing with benzol and ligroine, dried at 100°, and analyzed. 



0.1 0G6 grm. of the substance gave 0.0220 grm. of silicic dioxide 

 and 0.0584 grm. of sodic fluoride. 



Calculated for Found. 



(C 6 H B N(CH 3 ) 2 ) 3 (SiF 4 ) 2 . 



Silicon 9.81 9.63 



Fluorine 26.62 24.77 



The number for the fluorine is far from satisfactory, which is ac- 

 counted for by the difficulty of purifying this decidedly unmanageable 

 substance. It is, however, near enough to show that the substauce 

 can have no other composition than that assigned to it by us. 



Properties. — It forms an indistinct crystalline mass, which is de- 

 composed by heat, and gives no stable fluosilicate, when treated with 

 alcohol. 



Trichinoline Disilicotetrafluoride, (C H r N) 3 (SiF 4 ) 2 . — Chinoline 

 alone is not acted on by fluoride of silicon ; but, if the gas is passed 

 through a solution of chinoline in benzol, a gummy precipitate is 

 formed at first, which becomes gradually converted into needle-shaped 

 crystals. The product was purified by washing with benzol or ligro- 

 ine, and dried at 100°. The same substance is obtained when chino- 

 line fluosilicate is sublimed, and the analysis numbered II. is of a 

 preparation made in this way. 



I. 0.1634 grm. of the substance gave 0.0323 grm. of silicic dioxide. 

 II. 0.0730 grm. of the substance gave 0.0404 grm. of sodic fluoride. 



Properties. — It crystallizes in needles, and sublimes without melt- 

 ing, or decomposition. Although hot alcohol usually decomposes it, 



