800 
each other goes so slowly that the temperature which remains 
constant is found much higher for heating than for cooling. 
The limits found in this way for the transition point, are + 124° 
and 147°. The distance between them is, therefore, still greater than 
for ammonium chloride. (Cf. § 3). 
The velocity of conversion can, however, just as for ammonium 
chloride, be increased by the addition of glycerine. (Cf. § 6). Tie 
limits between which the transition point must lie, are reduced in 
this case to 187°.3 and 189°.5. Hence also with the catalyzer the 
distance remains greater than for ammonium chloride. Experiments 
with glycol as catalyzer vielded 137°.3 and 140°. 1. 
16. Vapour pressure measurements. 
I have determined the vapour tensions of the saturated solutions 
in an apparatus of the form as described by Lroporp). No more 
than for NH,Cl does the transition point express itself in the vapour 
TA Blote: dl, 
t | p 103 77! log p t (calc.) Error Series 
98.1 43.1 2.6947 1.6345 98.0 + 0.1 I 
110.35 63.6 2.6086 1.8035 110.5 — 0.15 ] 
116.75 16.65 2.5657 1.8845 116.75 ENT I 
126.0 99.8 2.5063 1.9991 126.0 0) | 
128.8 107.9 2.4888 2.0330 128.8 0 II 
129.3 109.1 2.4857 2.0378 129.2 + 0.1 lil 
134.7 125.8 2.4528 2.0997 134.5 + 0.2 I 
136.3 131.8 2.4432 2.1199 136.25 + 0.05 if 
141.0 149.5 2.4155 2.1746 141 .05 — 0.05 | 
144.0 1oie2 2.3981 2.2074 144.0 0 lil 
147.2 174.9 2.3798 2.2428 147.2 0 II 
147.45 175.8 2.3784 2.2450 147.4 + 0.05 I 
147.8 176.8 2.3764 2.2475 147.6 + 0.2 II 
153.4 204.0 2.3452 2.3096 153.4 0 I 
153.9 206.4 2.3424 2.3147 153.9 0 Ill 
154.8 210.3 2.3315 | 2.3228 154.65 + 0.15 Il 
157.5 pads ye 2.3229 2.3526 157.5 0 I 
1) Dissertatie Amsterdam (Sept. 1906), p. 64 et seq. 
