652 
MESSES. T. E. THOEPE AND J. W. EODGEE ON THE EELATIONS 
The calculated value for bromine is deduced from the dibromides, and its agreement 
with the observed value is satisfactory. In the case of the alcohols, however, it is 
at once evident that all trace of agreement between calculated and observed values has 
disappeared. The values of the alcohols, like that for water, are calculated by means 
of the constant for hydroxyl oxygen as derived from the acids. The calculated value 
for a tertiary alcohol is obtained on the assumption that two iso linkages occur in the 
molecule. In the case of the normal primary alcohols the first difference is positive, but 
all the others are negative, and increase as the series is ascended. It is also noticeable 
that an iso- or secondary isomer, gives a larger difference than the normal isomer, and 
a tertiary isomer gives the largest difference of any of the isomers. It is thus evident 
that there is a regularity in the magnitude of the deviations. Allyl alcohol also 
exhibits a comparatively large negative difference. As the behaviour of the alcohols is 
of the same nature with regard to the molecular viscosity work, we defer its detailed 
discussion till a later stage. 
Conclusions relating to Molecular Viscosity at Equal /S'Zoj^e. 
1. The tables indicate that at equal slope molecular viscosity for the great majority 
of the substances can be calculated from fundamental constants which express not 
only the partial effects of the atoms existing in the molecule, but also those due to 
different modes of atomic arrangement. 
The large effects which can be attributed to the ring-grouping of atoms, to the 
iso linkage, to double linkage, and to changes in the condition of oxygen in its 
compounds, as well as the smaller effects due to the accumulation of an atom of 
halogen in a molecule, make evident the quantitative influence of constitution. 
2. Of the remaining substances, the chlormethanes, tetracldorethylene, ethylidene 
chloride, and carbon bisulphide, give deviations from the calculated vmlues on account 
of constitutive influences, which for lack of sufficient data can not, as yet, be 
quantitatively expressed, and which are not allowed for in deducing the fundamental 
constants. 
3. The alcohols and water give no agreement with the calculated values. The mode 
in which the deviations vary indicates, in the case of the alcohols, that the disturbing 
factor is related to their chemical nature. 
