9 
We can now also calculate the critical temperature and pressure 
of Hg, and find (see $ 2): 
1), = 2 X 630° = 1260° (abs.) ; pr = 192 atm, 
as mercury is quite bimolecular at 7%. 
Also the missing critical pressures of the mercury halogenides, 
investigated by ROTiNJANz, can now be calculated. 
The following valae follows namely for fae ae 
28 bp 
For HgCl, : 
ately? «ise Ly OND 7.0%)? 
~ 98 (384)?. 10-10 sa( ge) eee 
For HgBr, : 
Ph: eer Ge perl == 00 atm: 
28 a 
484 28 
And for Hel: 
oS eS LG atm. 
28 - 
Pk 
1 /283\? (48,63)? 
pe =—( —- |= = 84 atm. 
28 \ 5,82 28 ae 
As the triple point temperature for mercury = — 38,84 + 273,09 — 
= 234°,25 abs., and the boiling point temperature = 356,7 + 273,1 = 
= 629°,8 abs, the ratios of these temperatures to the critical tem- 
peratures are resp.: 
ME 
Fr tT, —— 
The first value is still higher than the highest found value, viz. 5,2 
for Helium. Generally a value is found in the neighbourhood of 
2"), so that in the liquid state Hg has probably another molecular 
weight than at 7%. *) 
As to the second value, this too is considerably higher than the 
mean value for a great many normal substances, viz. 1,60. This 
’ 
1) It is certainly remarkable that the ratio Ts : Tyr lies either in the neighbourhood 
of 11/3 (e.g. CO,), or in that of 2 (for many substances), or in that of 27/3 (for 
several substances), or in that of 31/3 (for a smaller number of substances), or at 
last in that of 4 (e.g. for iso-pentane). These values differ every time ?/s of a unit. 
4 would be followed by 42/, and 51/, (for helium and mercury). We shall come 
back to this. 
[Fritz thought that this ratio would be either 1,2 or 1,8 or 2,7, but this is 
evidently not quite correct, as one can see oneself, when one determines the 
quotient Tk: Ts; for a great number of substances. See the Table further on]. 
2) Though it is less explicable then, that at lower temperature and smaller volume 
(two factors tending in the same direction) there would be less association present 
than at higher temperature. 
