216 Journal of the Asiatic Society of Bengal. [N.S., XVII, 
brought forward the theory connecting mass and molecular 
rotatory power. This now discarded theory gave rise to a 
large amount of experimental work, the results of which up to 
19064, have been summarised by Walden and since then up to 
1912 by Frankland In the light of more recent work this 
failure is of little significance as most of the work above referred 
to was carried on a class of compounds known as esters 
which are particularly prone to exhibit anomalous rotatory 
dispersion. Ethyltartrate has been fractionated into portions 
it. Theresult of this work also is not favourable to the theory, 
but certain regularities in a qualitative sense can still be traced 
init. Thus representing the compounds by the symbols Cabed 
and N (abed) X, the effect of increasing the size of d the 
“growing chain,”’ on the rotatory power depends on the size of 
(or the space occupied by) the other radicles a, b and c in the 
molecule. If the space occupied by a,b and e, is very small, 
the effect of increasing the size of d, on the rotatory power 
depends on its configuration. In the ‘“ methyl” series of car- 
binols, CH, CH (OH) R, the space occupied by a, bande is the 
smaliest conceivable (CH,, H, OH) and the values of the mole- 
cular rotatory powers of individual members in solution (ethyl 
alcohol and benzene) are considerably exalted when the whole 
molecule itself approximates to a ring structure, as in methyl- 
propylearbinol, and methyloctylearbinol, or when the growing 
chain in a similar manner all but returns on itself as in meth yl- 
amylearbinol and methyldecylearbinol : 
Normal Secondary Alcohols of the formula - 
CH3 CH (OH) R. 
R. (M)a (M)a (M)a20° (M)ab-p- 
é spvenricasd ; ons Benzene. (homogeneous state.) 
1 10°77° 10°3° 6°3° 
n-propyl 13°60 15°73 bd | 10°6 
n-Butyl 12-95 14 11-8 113 
n-amyl 13°28 90 12-0 11-4 
n-hexyl 12°73 16°77 12:7 117 
n-heptyl 13°10 16°98 12-9 12°1 
tyl 14-04 18°10 13°7 12°5 
n-nonyl 13°95 17°69 14-0 12°7 
n-decyl a k 
n-undecyl ee 14°74 17°48 144 13°7 
