218 Journal of the Asiatic Society of Bengal. [N.S., XVII, 
n the case of the substituted quaternary ammonium and 
azonium series, where the roups a, band ¢ are very large, 
the “ approximate maximum” is reached, when the growin 
chain contains three carbon atoms as in Phenylmethylbenzyl- 
ammonium series : 3 
(CgH;) (CH3) wo N—R. 
R. 
(alkyl group) for the ion in pana solution. 
thyl 
n-Propyl 299 
iso—Propyl 898 
-Butyl 253 
iso—Butyl| 323 
i myl 287 
This series also brlags out tek constitutive effect of the 
alkyl bbe on the rotatory pow 
The same is the case with Pe tnctiylallylmmakien 
series | 
(CsH5) (CH) (CsH;) N— 
. d 
(alkyl group) for the ion in aqueous solution. 
16° 
n—Propy! = 106 
iso-Propyl ie 103 
iso-Butyl : 55 
iso-Amyl a 18 
n the case of Phenylbenzylazonium series investigated 
by the writer, the molecular rotatory power increases rapidly 
with the length of the ‘‘ growing chain.” The “ approximate 
maximum” in this case cannot be determined as the series is 
not yet complete but from analogy it may be predicted that 
this maximum will i reached ‘when oes growing chain con- 
tains 3 or 4 carbon a 
ee (CoH) (Hie) N—R. 
(alkyl group) for the ion in secicbie solution. 
Ethyl Ke ee oe 
(Allyl) ie 137°1 
n-Propyl 45 247°5 
(6) Tue Errect or ConsuGatEp UNSATURATION : 
upe as the result of his earlier observations (Annalen 
1903, 327, 157) laid down the general rule that unsaturated 
groups usually produce an enhanced rotation, which falls off 
with the increased distance of the unsaturated group from the 
active radical. This early view was revised by him later on 
