258 PROCEEDINGS OP THE AMERICAN ACADEMY 



Properties of Triparatoluidodinitrobenzol. — This substance crys- 

 tallizes from a mixture of benzol and alcohol in characteristic acute 

 rhombic plates of a very dark purplish red color somewhat like 

 that of well crystallized potassic ferricyanide, but redder and more 

 purple. It melts at 197°, and is nearly insoluble in ethyl or 

 methyl alcohol ; freely soluble in benzol or chloroform ; sparingly 

 soluble in acetone or hot glacial acetic acid, almost insoluble in the 

 latter solvent when cold. 



If the dark brownish red plates of triparatoluidodinitrobenzol are 

 boiled with alcohol, the alcoholic extract deposits on cooling thread- 

 like felted crystals of a yellow color, which change to red in the 

 neighborhood of 180°, and melt at 197° like the original rhombic 

 plates. We have found it impossible, however, to convert the 

 whole of the plates into the yellow felted needles by this process. 

 To prove that the yellow crystals did not contain alcohol of crys- 

 tallization a portion of the preparation was heated to 120° until con- 

 stant, when it was found that the loss was not more than would be 

 mechanically retained by such a very spongy substance. The dried 

 substance was then analyzed with the following result : — 



0.2096 gr. of the substance gave 26.9 c. c. of nitrogen at a tern* 

 perature of 27°. 5 and a pressure of 758.6 mm. 



Calculated for C 6 H(C 7 H 7 NH) 3 (N0 2 ) 2 . Found. 



Nitrogen 14.49 14.10 



We should add that 0.3991 gr. of the dark red plates air-dried 

 when heated to 100° for four hours lost only 0.0004 gr., so that 

 this substance also is free from alcohol or benzol of crystallization. 

 These observations show that the triparatoluido compound appears 

 in two forms similar to those discovered with the anilido compound. 

 Some other solvents beside alcohol convert the red form partially 

 into the yellow, notably ether and acetone. 



Triorthotoluidodinitrobenzol, C 6 H(C 7 H 7 ISriI)3(N"02)2- 



This substance was most conveniently prepared by adding 12 gr. 

 of tribromdinitrobenzol to 35 gr. of boiling orthotoluidine, stir- 

 ring the mixture, and allowing it to cool as quickly as possible to 



