place. So the question remains whether two lines OB and O/D’ can 
be drawn so that they show a point of transition at 184,5°, that 
the heat of conversion of § 10 corresponds with the angle between 
the lines, and that the observed points depart from these lines within 
the errors of observation. As when we use the mode of represen- 
: aA ee a Q 
tation of figs. 4 and 5 the slope of the lines is indicated by a 
it is clear that the angle between the lines O’B’ and O’ D’ of fig. 3, 
transferred to figs. 4 and 5, will be a direct measure for the differ- 
ence in heat of evaporation, and will, therefore, have to amount to 
1,03 , ‚ 
-— the difference in heat of evaporation at the transition tem- 
t 
perature being equal to the heat of transformation of 1,03 kilogram 
calories determined in § 10. 
TABIEESS: 
ne ed ak EES 
280 | 135.0 | 0.668 | 1.429 | 1.808 
290 | 185.3 | 0.660 | 1.579 | 1.776 
300 | 252.5 | 0.652 | 1.726 | 1.745 
310 | 341.3 | 0.644 | 1.869 | 1 715 
320 | 458.1 | 0.636 | 2.008 | 1.686 
330 | 610.6 | 0.628 | 2.145 1.658 
In table 8 the two first columns give the corresponding tempera- 
tures and pressures according to Smirn; they correspond therefore 
with the line OB of fig. 3 and with the asterisks of fig. 4. In the 
third column the degrees of decomposition are recorded of the saturate 
vapour, which Smira has calculated from his observations as the 
most probable. The fourth column gives the value of log p‚ in which 
p represents the partial pressure of the unsplit part in the vapour. 
It is clear that the relation 
holds between p and P. 
These values of p refer, therefore, to the line O’B’ of fig. 3. 
The last column gives the value for 7~1!. In fig. 5 the calculated 
values of columns 4 and 5 of table 8 are graphically represented 
