I 99 
1880 .] New Scientific Processes and Inventions . 
the Fournier process ; Glauber’s salt is deposited in a fine crys- 
talline mass, whilst chloride of magnesium— an article now 
largely consumed for weighting textile fabrics — remains in so- 
lution. . r 
M. Pechiney proposes a very ingenious process tor converting 
this hydrated sodium sulphate into the anhydrous salt, known in 
the trade as salt-cake. About 1500 kilos, of the crystalline paste, 
previously drained, are placed in a wooden cistern fitted with an 
agitator, and dissolved in a little of the mother-liquor with the 
aid of steam introduced by a copper worm. When the whole is 
dissolved, 250 kilos, of common salt are added. An exchange 
now takes place ; the salt gradually dissolves, and the sulphate 
is deposited in its stead, but in an anhydrous condition. This 
sediment is then transferred to a filtering-vat with a double per- 
forated bottom, and allowed to drain. It is thus obtained free 
from all foreign matter, save about 5 per cent of water and 0-5 of 
common salt. 
It is highly probable that the processes here described may 
point the way to further applications of low temperatures in the 
chemical arts. 
J. W. Slater. 
