108 
DRS. W. RAMSAY AND S. YOUNG ON SOME OF 
tures have been determined by us (‘Chem. Soc. Trans./ vol. 47, p. 640). By causing 
one or other of these liquids to boil under definite known pressures, any desired 
temperature, within certain limits, was attainable ; and, as a small alteration of tem¬ 
perature corresponds to a considerable alteration of pressure, it may be taken for 
certain that the temperatures are practically correct. The expansion of the glass 
made use of for the volume tube was carefully determined, and a correction was in all 
cases applied, so that the apparent volumes are reduced to real volumes. No correc¬ 
tion, however, was applied for the alteration in the volume tube due to internal 
pressure, because an estimation of its amount showed it to be much within the error 
of reading volume. 
The results may be classified under three heads :— 
I. Expansion of liquid water. 
II. Vapour-pressures. 
Ill Density of unsaturated and saturated steam. 
I. Expansion of Liquid Water. 
For these experiments, the tube was two-thirds filled with water freed from air by 
boiling in vacuo. That no air was present was often proved during the experiments 
by condensing a bubble of steam; condensation always took place without appreciable 
rise of pressure. The weight of water taken was deduced from observations of its 
volume at the ordinary temperature, both before and after experiment. The results 
are as follows :— 
Temperature. 
Divisions of tube. 
Volume at 4 and weight. 
o 
c.c. or grm. 
i 
12-25 
246-75 
1-1054 
1 
L12-40 
246-90 
1-1060 
J 
r 15-7 
246-20 
1-1031 
1 
L17-9 
246-25 
1-1035 
The first pair of readings w r as taken before the commencement of the experiments ; 
the second pair after the expansions had been measured. The small difference is 
probably due to adherence of liquid to the lower portions of the tube, which had 
become etched during the experiments. 
The mean result, from which the following Table is calculated, is D1045 c.c. at 
4°, or IT045 grm :— 
