1922.] Indian Science Congress... ° I18.C. 71 
would ane specially fast aves! Hat the properties of azo dyes sete 
from hydroxy naphthyl mercaptans so that the hydroxyl groups would 
i o-linkin i i 
tae”, oun 
aphthol in alkali, it was hoped that these dyes woul 
o Bn 
seems eat: - (3) the ES Ges. of azo-dyes containing mercaptan paraaleee 
on both sides of the azo- Pade 
The action of nitric acid on metals and some alloys.—By 
os C. BANERJI. 
It has been observed that metals aon copper, silver, lead, nickel and 
alloys like — silver-oin copper, nickel, ~~ ., dissolve more readily in 
arn acid in the presence of ferr ous, and ferric salts. 
his is ae rary to tls accepted v 
xidising agents exnt MnO, KClOy 'H,0», K,Cr,0;, ete., markedly 
gene oe stp solut 
e of alain ‘of ferro-nickel alloy in 20% HNO; isnot uniform, 
but hee Watiee is periodic 
Oxidation of ferrous sulphate by air.—By P. x. BANEBJI. 
The rate of oxidation of ferrous sulphate by air does not pce ex- 
actly the unimolecular formula, ut the Satine approxim mates t ¥ 
The — hourly oxidation of a deci normal solution at sbau $2 Cc 
is bebe tad en the experiments are spread over 1,488 hours. - 
aofin sulphate, magnesium sulphate, z ulphate, mangane' 
ammonium sulphate, are slight retarders and sulphuric acid and 
phat 
ober sulphate ee great retarding effect. Only potassium sulphate s 
a slight accelerator. 
Studies on the Dependence of Optical Rotatory Power 
on Chemical Constitution, Part IV : The Rotatory a 
of Aryl Derivatives of Hisimino-and-aminocampho 
— K. Sinan, M. Stneu and J. Lat. 
his paper the rotatory power of the se he of condensing 
causphevantone with the following diamines are descr 
(a) hydrazine; (6) benzidine ; (c) tolidine ; (d) saitaiaind (e) Pp» P’> 
ee Lie amine. 
Benzidine and tolidine giv 
dine pepe only one. The two forms are re 
rical isomerides, since in the — oe ett 
e two precel 9 aleve shor ee 
arde| as georne 
ne path’ ae cog give the 
tive on reduc 
The effect of ortho- erative on the rotatory power 2 ea Ag 
diphenylene-bisiminocamphot ([M]p 5432° and 5472° in os Xai he 
casos of 0, 0! It is accompanied by low ve a, Sort aad 3 407°). sea 
( .2003°). The sequence 
f oF o’," ditolylenebisiminocamphor ( : 
anes diminishing rotatory 

0,0’, 
of the substituent element or group in ng 
power in this series is H > CH3> ith 
he product of condensing camph eames. We ae the highest 
diphenylamine is remarkable in several ways. 14740° in pyridine), 
ecular “ power hitherto recorded (Mp. Fanaa 
ts the mélecalar rotstory power of 1.14 Nepiey O. 
bia tines oe r (Singh : ane Bin ht. 1930, 117, 1599). *" 
and Sue ae® pho a har opti Cor, active dyes known. {t is both thermo- 
Were and phototroet ic. 
p’, diamido- 
