ON EVAPORATION AND DISSOCIATION. 
105 
found to be identical at 181'0°. Here, again, it is noticeable that the results of the 
two methods are widely divergent. (Plate 2.) 
§ 58. Aldehyde-Ammonia, CH 3 .Ch|q^ 3 .—This substance was suspected to decom¬ 
pose on heating, in spite of Schroder’s having found its vapour-density normal at 
160° (‘ Berichte,’ 4, p. 470) ; and it will be seen later that our experiments prove the 
justice of this conclusion. The substance smells at once of aldehyde and ammonia. 
It is said to melt between 70° and 80°, and to distil undecomposed at 100°. 
59. Pressures of Dissociation in Barometer-tube. 
Temperature. 
Pressure. 
Duration of experiment. 
O 
millims. 
21-3 
7-0 
12 hours. 
28-9 
13-5 
83 minutes. 
39-7 
32-9 
88 „ 
45-2 
49-8 
27 „ 
50-0 
83-6 
Not constant after 249 minutes. 
54-6 
144-2 
!, » 718 ,, 
55-7 
176-2 
Constant after 75 minutes. 
60-60-8 
307 4 
Not quite constant after 25 hours. 
It was evident from the discoloration of the substance at the higher temperatures 
that it had partly decomposed ; the results, however, point to gradual dissociation, 
accompanied at the higher temperatures with some decomposition. The curve is 
given in Plate 2. 
§ 60. Temperatures of Volatilization of Aldehyde-ammonia. 
The condenser was cooled by a freezing mixture. The thermometer-bulb was 
covered with cotton-wool, and dipped repeatedly into the melted substance. The 
tube was jacketed with the vapour of chlorobenzene. 
Series I.—Pressure raised by admitting Air. 
Pressure. 
Temperature. 
Pressure. 
Temperature. 
Pressure. 
Temperature. 
millims. 
O 
millims. 
O 
millims. 
O 
2-8 
26-1 
33-0 
56-2 
403-3 
78-2 
3-25 
29-2 
63-4 
61-5 
53-3 
60-3 
3-85 
33-2 
124-1 
67-2 
5111 
81-2 
8-5 
42-7 
265-0 
74-2 
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