( 507 ) 
vapour. Moreover, the fact that in our tubes the pressure exceeded 
1 atm. showed that at 1 atm. solid bromine (or the mixed erystals) 
would be in equilibrium with a gas-phase which contains much more 
HBr; from this we deduced that the liquid- and the vapour branches 
of the f,z-curve for constant pressure (the boiling point line) are 
much diverged. We tried to prove this by passing gaseous hydrogen 
bromide through bromine at 0° and analysing both the liquid and 
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the gas. The bromine was placed in a tube furnished at the bottom 
with a tap by means of which the solution saturated with HBr 
could be removed. The hydrogen bromide which had bubbled through 
the bromine was passed through a tube furnished with stopeocks at 
both ends, from which it finally emerged in a flask over water. 
After the gas had passed for some time so that it might be taken 
for granted that the bromine was saturated and the tube completely 
