600 
MESSRS. T. E. THORPE AXD J. W. RODGER OX THE RELITIOXS 
(4.) The effect of molecular -weight is iu some cases more than counterbalanced 
by the effect of constitution or of complexity. 
(5.) The lowest members of homologous series frequently exhibit deviations from 
the regularities shown by higher members. 
(6.) An iso compound has, in general, a larger coefficient than a normal compound, 
and the differences reach then maximum in the case of the alcohols, 
(7.) In the case of other metameric substances, branching of the atomic chain and 
the symmetry of the molecule influence the magnitudes of the coefficients ; the ortho¬ 
position, in the case of aromatic compounds, appears to have a more marked effect on 
the coefficient than either the meta- or para-positions. The isomeric normal alcohols 
give values which are almost twice as large as those of acetone and ethyl ethei-. 
(8.) One of the most striking points thus brought to light is the peculiar behaviour 
of the alcohols, and to some extent of the acids, as contrasted with that of other 
liquids. 
IMoLECULAE YiSCOSETY {-q X SPECIFIC MOLECFLAE AREA = AT THE BOILIXG-POIXT. 
[rj in dynes per scp centim. X specific molecular area in sq. centims. X 10'^). 
Homologfes. 
vdh 
Difference. 
Pentane . 
480 
70 
Hexane . 
550 
43 
Heptane. 
593 
Octane .. 
646 
Isopentane. 
489 
Lsoliexane. 
551 
QT 
IsoEeptane. 
588 
O i 
Isoprene . 
415 
68 
Diallyl. 
483 
^letEyl iodide. 
639 
Ethyl iodide. 
721 
74 
Propyl iodide. 
795 
Isopropyl iodide. 
816 
46 
Isobntyl iodide. 
862 
