680 
MESSRS. T. E. THORPE AND J. W. RODGER ON THE RELATIONS 
the same as at the smaller slope, the values of the isomeric aromatic hydrocarbons do 
not arrange themselves in the same order. Of the isomeric xylenes the ortho-isomer 
has still the largest molecular viscosity work, but para-xylene has now a value which 
is slightly larger than that of meta-xylene. The value for ethyl benzene is no longer 
intermediate to that of ortho- and meta-xylenes, but is the greatest of all the values 
given by the four isomers. The numbers are now in the same order as the magnetic 
rotations of the substances. Whether these small variations in the relative magni- 
tudes of the values of the molecular viscosity work are real, or merely the result of 
Imperfections in Slotte’s formula, cannot at present be definitely decided. 
The halogen compounds, and water, which are not included in the preceding table, 
give values which are related to those of the other compounds in the same way as at 
slope • 04 , 323 . This is seen in the following table, where the observed values of the 
lialogen compounds at the two different slopes are compared with the values calculated 
hy using the value of chlorine in monochlorides. The calculated value for Avater is 
obtained from the value of hydroxyl oxygen deduced from the acids. 
Slope •0,^323. 
Slope -O^OS?. 
Ohs. 
Cal. 
Diff. 
per cent. 
Obs. 
Cal. 
Diff. 
per cent. 
Ethylidene chloride . 
312 
338 
8-3 
578 
634 
9-7 
Chloroform. 
328 
.381 
IGT 
615 
715 
16-2 
Carhon tetrachloride 
406 
504 
24'1 
751 
946 
26-0 
Tetrachlorethylene . 
497 
557 
12-1 
903 
1045 
1.5-7 
Water. 
.5.5 
30 
— 45.5 
105 
56 
- 46-6 
From the agreement between the magnitudes of the pei-centage differences giA'eii 
at the two slopes, it is evident that the peculiarities exhibited by these substances at 
the smaller slope still persist at the large slope, and are thus independent of the value 
of the slope at which the comparisons are made. The discussion of the values of 
these substances already given at slope '04323 is thus applicable to the values at slope 
•O4987. 
As already pointed out, the agreement of the differences in the case of water and the 
beliaviour of the fatty acids at the widely separated temperatures of the two slopes 
indicate that even in the case of liquids such as these which contain molecular 
aggregates, the relationships obtained are also independent of the particular value of 
the slope at which the comparisons are made. 
