38 
DRS. W. RAMSAY AND S. YOUNG ON THE INFLUENCE OF 
volatilizes under the same pressure, yet it has never been satisfactorily proved. It is 
true that Mr. J. B. Hannay states that in experiments performed to disprove the 
possibility of raising the temperature of ice above 0°, for which a Florence flask was 
used, the bulb being placed in a freezing mixture, while the neck, in which a 
thermometer surrounded with ice was suspended, was heated by a Bunsen’s flame, 
the temperature of the bulb or condenser was nearly identical with that of the ice. 
From our experiments we know that the temperatures of the freezing mixture and of 
the condenser are never identical, and Mr. Hannay failed to describe any arrange¬ 
ment by which the internal temperature of the condenser could be found. 
Fig. 1. 
The experiments of Petterssen are more conclusive. By connecting the apparatus 
with a manometer he found that when the block of ice surrounding the thermometer 
was at any given temperature, the pressure in the manometer roughly corresponded 
to the vapour-tension of ice at the same temperature; but as he published the results 
of only two experiments, and as the errors are comparatively large, the question could 
not be regarded as settled. 
3. We resolved first to study the behaviour of ice at low pressures. For this 
purpose an apparatus was constructed which we afterwards found to have some 
resemblance to that described by Boutlerow (I. Buss. Phys. Cliem. Soc., 1881, i., 
316). The annexed figure (fig. 2) shows its form. 
It was found that the leakage of air into the apparatus through the indiarubber 
connexions was extremely minute, and that an almost perfect vacuum could be main¬ 
tained for several days. *• 
4. The plan of operation was as follows Both bulbs were filled with water 
through the opening at E, and the water was boiled down until reduced to the volume 
of the bulb B. While the water was boiling, the screw-clip at E was closed, and the 
flames then removed. After cooling, the water was transferred to B, which was 
placed in a freezing mixture. When the water was frozen the bulb was gently 
