164 Journal of the Asiatic Sociely of Bengal. {N.S., XVI, 1920.] 
the proper S. G., the S.W.A. would be returned to the Acid 
Section weaker than is demanded and increased cost of recovery 
would result. 
The application of the principle of this simple apparatus 
is general for al! liquids, the run-off of- which is controlled 
by S.G. ‘ 
In The Chemical Trade Journal and Chemical Engineer 
of May the 3rd, 1919, Colin Sutton describes an apparatus for 
the control of the run-off of the waste acids from guncotton 
dipping pans. At Aravankadu, the exit pipes from the pans 
are made of lead. By trial, the diameter of this run-off pipe 
could be made of such a size that, when the cock is full open, 
the acid from one set of pans would get awav in three hours. 
Owing to corrosion, the diameter of the tube would change, 
but, by fixing a glass tube of the requisite diameter in the end 
of the run-off pipe, the variation in the flow due to corrosion 
he models were designed in collaboration with Mr. L. W. 
Pryor, Foreman of the Guncotton Section in this Factory. I 
wish to express my appreciation of the courtesy of Mr. J. C. 
Bain, Chief Foreman Plumber, and his staff who skilfull y con- 
structed models of the various forms of the apparatus for 
experiment and demonstration. 
Cordite Factory, 
Aravankadu, 
S. India. 
ON NINN INS NS NPR PRS NS wrt 
