62 
The practical bearing of onr results would seem to be 
upon (1) the “ causticizing process/’ and (2) on the “black 
ash” process of the soda manufacturer. In the first case, 
as already mentioned, the residual soda is kept in circula- 
tion in the process, and so is not lost, the lime-mud being 
drained, and used again in the black ash mixture. In some 
works, however, where black ash is not made, e.g., soap 
works, causticizing from soda ash, &c., an average loss of 
about 7£ per cent Na 2 CO s of the dry residue or 4*7 per cent 
of the washed and well-drained mud, is sustained. In the 
second case, it is evident that an adequate improvement, 
by which a minimum amount of calcium carbonate is used 
in the black ash mixtures, must effect an improved yield of 
soda or lixiviation, a smaller retention as insoluble com- 
pound in the soda-waste occurring. Wright’s results and 
remarks on this head, are valuable. (See his paper, already 
cited — Part I). 
