110 FLUIDITY AND PLASTICITY

TABLE XXIII.—THE VALUE OF UYDUOOEN

Substance
n
Cu2H7H.2
nCH2
H2

5
329
400
-71

Normal paraffins
6
7
415 495
480 560
-05
-65

8
574
640
-66

( 5
320
392
-72

Iso-paraffins
6
405
472
-07

i 7
482
552
— 70

and Rodger remark (p. 643), "If such differences are confirmed
by more numerous observations, viscosity will rank as one of the
most useful properties in determining the constitution of oxygen
compounds.77 They then add, "It is, of course, to be remem-
bered here that the value of hydroxyl oxygen as it is derived from
the acids is no doubt affected by molecular complexity.77
Using the constants obtained as above, and grouped together
in Table XXIV for reference, Thorpe and Rodger calculated the
values of the molecular viscosity work for the substances given
in Table XXII, and reproduced in column 4. The average dif-
ference between the observed and calculated values is less than
1 per cent, but it is to be remarked that water and the alcohols
do not enter into comparison at this particular slope. At a differ-
ent slope they were able to bring these substances into the
comparison, and they found a very great divergence between
the observed and calculated values amounting to 44 per cent in
the case of dimethyl ethyl carbinol and 47 per cent in that of
water. Again the difference was partly attributable to constitu-
tive influences, since it was noted that the divergence is least in
the primary and greatest in the tertiary alcohols. But at the
same time they note that these compounds are most certainly
associated and the theoretical values of the molecular weight were
used in place of the actual values. They conclude their study
of molecular viscosity work at equal slope with the following
noteworthy statement: "The results here obtained are of
precisely the same nature as those discussed under molecular
viscosity. More detail has been given to show that the sub-
stances which give deviations from the calculated values fall