28 PROCEEDINGS OF THE AMERICAN ACADEMY 



pound, that is, by passing fluoride of silicon through a solution of 

 paratoluidine in beuzol, but even after four sublimations it had a dis- 

 tinct yellowish color; that the substance is essentially pure, however, 

 in spite of this coloration, is shown by the following analyses. 



I. 0.1928 grm. of the substance gave 0.0438 grm. of silicic dioxide. 

 II. 0.1472 grm. of the substance gave 0.0022 grm. of sodic fluoride. 



Calculated for Found. 



(O^NH^SiF^j. I. II. 



Silicon 10.58 10.G0 



Fluorine 28.73 . . . 28.34 



In properties it resembles the corresponding ortho compound, but 

 is decidedly less stable, showing a strong tendency to turn yellow on 

 standing, and the paratoluidine fluosilicate deposited, as the hot solu- 

 tion of the substance in alcohol cools, crystallizes in thick needles. 



Trimonochlor -aniline Disilicotetrajlaoride, (C 6 H 4 ClNHo) 3 (SiF 4 ) 2 . — 

 This substance was made by passing fluoride of silicon over para- 

 chloraniline, and was purified by sublimation. Its composition was 

 determined by the following analysis. 



0.4807 grm. of the substance gave 0.0990 grm. of silicic dioxide, 

 and 0.2G86 grm. of sodic fluoride. 



for 



Found. 



9.61 

 25.29 



It resembles the corresponding aniline compound in its properties, 

 and forms with hot alcohol a solution of the parachloraniline fluosili- 

 cate, which separates as the solution cools in beautiful long slender 

 needles. 



Parabromaniline forms a similar compound with fluoride of silicon, 

 and gives with hot alcohol a solution depositing the parabromaniline 

 fluosilicate in small pearly scales. 



With symmetrical tribromaniline we could get no action, when we 

 treated it with fluoride of silicon, the result of the experiment being 

 negative, whether it was acted on alone in the solid state, or fused, or 

 in solution in benzol. Symmetrical tribromaniline therefore does not 

 combine with fluoride of silicon under the conditions which bring 

 about the union with it of all the other bases studied. 



Tridiphenylamine Disilicotetrajluoride, ((C 6 IF) 2 NH) 3 (SiF 4 ) 2 . — 

 Solid pure diphenylamine is not acted on by fluoride of silicon ; the 



