108 PROCEEDINGS OF THE AMERICAN ACADEMY 



form salts than the triarnidotrinitrobenzol, which is insoluble in strong 

 hydrochloric acid. 



Trichloride of Pentamidobenzol, C 6 H(NH 2 ) 2 (NH,C1) 3 . 



To prepare this substance, some of the triamidodinitrobenzol (either 

 the crystalline or amorphous) was heated on the water bath in a flask 

 with strong hydrochloric acid, a very strong solution of stannous chlo- 

 ride, granulated tin, and some pieces of platinum foil. After some 

 hours the very deep red solution had lost most of its color, but still 

 showed a dirty brownish yellow tint ; it was then allowed to cool, when 

 crystals were deposited, which increased in quantity, if the liquid was 

 saturated with hydrochloric acid gas. The crystals were filtered out, 

 and washed with concentrated hydrochloric acid, then, as we did not 

 succeed in removing the salts of tin completely by precipitation from 

 an aqueous solution with hydrochloric acid gas,* the substance was 

 dissolved in very little water and the solution saturated with sulphu- 

 retted hydrogen, the stannic sulphide formed was filtered out, and the 

 filtrate, after freeing it from sulphuretted hydrogen with a stream of 

 air, once more saturated with hydrochloric acid gas, which threw down 

 the substance in an essentially pure state and nearly white. In all 

 this work care must be taken to avoid heating the solutions, as the 

 chloride of pentamidobenzol, after the reducing agents have been re- 

 moved, is easily decomposed by heat into a black tar ; the solutions, 

 therefore, should never be concentrated by evaporation on the water 

 bath. "We obtained a less pure substance also, if the solution in water 

 and precipitation with hydrochloric acid gas was repeated more than 

 once. The crystals were dried at first in a desiccator over calcic oxide, 

 calcic chloride, and potassic hydrate, and finally heated to 70°-80° for 

 about five hours in an air bath. On analysis they gave the following 

 results. 



I. 0.2372 grm. of the substance gave on combustion 0.2445 grm. of 

 carbonic dioxide and 0.1157 grm. of water. 

 II. 0.1827 grm. of the substance gave 0.1880 grm. of carbonic dioxide 

 and 0.0880 grm. of water. 



III. 0.1533 grm. of the substance gave 35.8 c.c. of nitrogen at a temper- 



nature of 14°. 2 and a pressure of 750 mm. 



IV. 0.1 457 grm. of the substance gave according to the method of Carius 



0.2377 grm. of argentic chloride. 



* Barr succeeded in removing all the tin from his preparation in this way. 



