430 



GIBBS. 



ANILINE IN DRY HYDROGEN, HYDROGEN AND MOISTURE, AND 

 DRY CARBON-DIOXIDE. 



Purified aniline was sealed in atmospheres of dry hydrogen, moist 

 hydrogen and dry carbon-dioxide by means of the apparatus shown in 

 figure 1. The manipulation was the same as previously described except 

 that the tube a was not sealed, but during the distillation was connected 

 with a current of the desired gas. The gases were purified by the 

 proper absorbing and drying chains. 



Tube 

 No. 



Gas. 



Dry hydrogen 



do 



do 



do 



Hydrogen and moisture 

 Dry carbon-dioxide 



In sunlight. 



From— 



June 4, 1909 



do 



June 10,1909 

 June 15,1909 

 June 11,1909 

 June 17,1909 



To— 



June 17, 1909 



Do. 

 Aug. 3, 1909 



Do. 



Do. 



Do. 



Numbers 1 and 2 colored in one-half an hour and finally became a 

 brilliant red. Numbers 3 and 4 were not observed in the initial stages 

 of the coloration. They finally became very dark, brilliant red. Number 

 5 became reddish-yellow and number 6 yelloAV. 



ANILINE IN EULL TUBES. 



Two tubes, as full of purified, colorless aniline as it was possible to 

 seal them, were placed in the sun upon a white porcelain plate on 

 August 9, 1909. The pressure, due to the expansion of the aniline in the 

 heat of the sun's rays broke one of the tubes. The other was opened on 

 August 2, 1910. 



These tubes showed a slight yellow coloration in less than one-hour's 

 exposure to the sunlight. The unbroken tube after almost a year's 

 exposure to the light was red in color. 



The contents of the tube measured 45 cubic centimeters. A first portion 

 of 10 cubic centimeters was heated in a very small distilling flask, the delivery 



tube of which dipped under 5 cubic centimeters of — hydrochloric acid, colored 



with a drop of methyl orange in a test tube. As the temperature of the 

 aniline rose, evolution of gas took place. Before the boiling point was reached 

 and before any but the smallest traces of aniline could have passed over, the heat 

 was removed. The top layers of the hydrochloric acid solution became alkaline 

 as shown by the change in color of the indicator. On shaking the solution it 

 was found still to be acid. This solution was evaporated over calcium chloride in 

 a desiccator at room temperature. Ammonium chloride crystals separated and on 

 treatment with potassium hydroxide solution the unmistakable odor of ammonia 

 was very strong. No odor of aniline was detected. 



A second portion was distilled until about twenty drops of aniline had 

 passed over into the hydrochloric acid. The excess of aniline was then removed 

 by distillation in steam, the solution filtered and the filtrate evaporated to 

 dryness on a water bath. This residue sublimed ammonium chloride on gentle 



