226 Journal oj the Asiatic Society of Bengal. [N.S., XVII, 
It has thus become clear that we have as yet no rule 
which can apply to all the cases hitherto investigated and the 
most important point which has emerged from this work is 
that the nature of the solvent playsa considerable part on the 
order of rotation of position isomerides. The conclusion is 
naturally forced on us that this problem is much more compli- 
cated than was anticipated by Frankland and others. 
The effect of position isomerism on optical rotatory power 
in the case of the naphthalene nucleus has also been studied 
by the writer. It is found that the substituent in the (-posi- 
tion has somewhat higher rotatory effect than in the a- 
position. 
(M)a (M)a 
{ chloroform. Methyl alcohol. 
Naphthyliminocamphor } ea os her vue eee 1625° 
B 1985 1893 
: a 267°5 210 
Naphthylaminocam phor { B 417-8 366°2 
But experience already gained from similar work warrants 
the supposition that it is possible that this relation may not 
hold in all cases. 
Tue WaLpDEN INvuRsion: 
I wish now to draw your attention briefly to a remarkable 
Inversion, first described by Walden in 1296, as shown in the 
following scheme :— 
Il-chlorosuccinic 
acid. 
wo <tels Malic acid. 
: KOH 
-aspartic acid. | A820 ASe20 
ee ‘ Pels d-chlorosuccinic 
fc) 1- Malic acid. — acid. 
————— 
KOH 
c loride, or is first replaced by hydroxy group bv means 
of nitrous acid, the hydroxyl being subsequently replaced by 
chlorine with the aid of phosphorus pentachloride. Further 
laevorotatory or dextrorotatory “chlorosuccinie acid ean be 
