(173) 
120 
119 ed 
118 IN IN 
117 \ ‘ 
116 \ = 
115 . oN 
414 B ax 
113 
412 
111 
110 
109 
108 
107 
106 
105 
104 
103 
102 
101 if 
5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 
hydrazine in the liquid and condensed vapour, it was impossible to 
avoid contact with the atmosphere. The operation was carried out 
in such a manner that each time after distilling off a certain quan- 
tity (LO—20 cc. in the case of the greater concentrations), two por- 
tions (3—4 drops) of the condensed vapour and residue were simul- 
taneously collected in tared weighing bottles containing about 5 ec. 
of water. On account of the many weighings a certain time neces- 
sarily elapsed between the taking of the samples and the titration 
and, considering that the bottles also contained a little vapour of 
hydrazine mixed with air, this must have excercised some influence. 
A vapour 
B liquid 
This explains why the agreement between the various duplicate 
determinations often left much to be desired; in one case a discre- 
pancy occurred amounting to 2 mols. per 100. Finally, another 
source of error is found in the fact that on account of the many 
weighings and titrations, the determinations had to be done on dif- 
ferent days, so that the distillations were conducted under different 
barometric conditions. 
Notwithstanding this, the results allow of the construction of a curve, 
the regular course of which is a guarantee that the figures observed 
12 
Proceedings Royal Acad. Amsterdam, Vol. V. 
