11, The Automatic Control of the Separation of a Liquid 
into Fractions limited by Specified Densities. 
By Horace Barratr DUNNICLIFF. 
Published with the permission of the Indian Munitions Board. 
The special application of the apparatus to be described 
to the work at the Cordite Factory, Aravankadu, S. India, is 
in the running off of the strong and weak waste acids from the 
dipping pans used in the displacement process for the manu- 
facture of guncotton 
The acid, which is recoverable after the cotton is nitrated 
in the pans, is aa off in two separate portions called strong 
waste acid (S.W.A.) and weak waste acid (W.W.A.). With 
the assistance of the appliance to be gee it is possible, 
without supervision, to run off the 8.W.A., th W.W.A. and © 
the unrecoverable residues into their proper ‘eepelisie, pro- 
vided that it is known at what specific gravity (S.G.), the acid 
ceases to be S.W.A. and at what S.G. it is desired to sto 
the W.W.A. and to pass the rest of the runnings (unrecover- 
able) to waste down the dra 
e principle is a general one and capable of utilisation in 
connexion with other similar 
weight is ever so little greater A 
than the 8.G. of the liquid 
multiplied by the volume of 
the body. —- 
Thus: suppose that | "8 
liquid of 8.G. 1°3 is sanite 
from - vessel, A, Fig. 1, and D 
s 8. 
falling. Suppose that it is 
desired to stop the flow of 
the liquid through the pipe, B 
B, when the S G. of the liquid G 
8.G., 1:2. The body em Fie. 1. 
float in the liquid until 
8.G. of the Hqaid i is 1:2 and immediately the 8.G. falls 
