1919 } The Sixth Indian Science Congress. CCXXVIi 
ing factor in many Indian soils and said that caution was necessary in 
the crear ate application of nitrogenous manures as under such 
tion o i 
easily r n portion of the n prese the soil is 
i orm immediately available for plant food, the roportion available 
pe nm th e at which the breaking down of protein m r 
eget are ing p The protein fermentation may easily take 
e direction leading to an accumulation o od not 
deeeuy partite whi t time owing t intensive cultivation 
t oohydrate material in the soil is greatly diminished, wi ~ 
g ase in nit n assimilatio ences if i ve methods of 
cultivation ob aintained these losses g 
addition of nitrogenous mate und fully controlled conditions 
P 
question which it is at present difficuit to answer and involves such ques- 
tions as the limiting of exports of oil seeds and the electrolytic production 
of nitrogenous compounds. These are questions which will soon hav ve to 
be faced if the ultimate impoverishment of Indian soils is to be avoided. 
Colloids and their relation to industry.—By R. L. Mac- 
KENZIE WALLIS. 
After a general introduction the writer dealt particularly with the 
— t of protective colloids, instancing the use of dextrin, starch, etc. H 
or the prevention of boiler scale, the use of gelatin in electro-plating to 
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au ork on casein, e.g. the 
me of preparatio pure casein and its behaviour with various 
Lmcifoniys pomeggge vk Pyridine, A glue powder, of great adhesiveness 
oiste 
ic t 
for farina in sizing, for water-proofing canvas, for protecting stone- 
work and preventing corrosion of metals. 
The following Public Lectures were delivered :— 
“The Life-History of a Star.” —By Dr. GILBERT T. WALKER, 
CO.8.L,, , F.B.S. 
“‘ Waves in the Air and in the Aether.’ "— By C. V. Raman, 
Esq., M.A. 
« Taotios’ against Insects.”—By F. M. Howtezrt, Esgq., 
B.A., F.E.S. 
