( i9 6 ) 
[March, 
EXPLANATORY REPORTS ON NEW 
SCIENTIFIC PROCESSES AND INVENTIONS. 
[These Reports will not partake of the nature of an Advertisement, but will 
be impartial descriptions.— Ed. J. S.] 
Applications of Artificial Cold in Industrial 
Chemistry. 
No fa<5t is more familiar to scientific men than that the behaviour 
of substances brought in contact is powerfully modified by the 
temperature to which they are submitted, the results produced 
being affefted not merely in degree, but sometimes even in kind. 
But whilst in manufaauring operations temperatures . ranging 
from the average heat of the atmosphere up to the melting-point 
of platinum have stood at the disposal of the technologist, and 
have been applied as requisite, it is only of late that what is 
familiarly known as cold—i.e ., temperatures below the freezing- 
point of water— has been made available on a practical scale. 
The following examples will at least show that the freezing- 
machine, as the antipodes of the furnace, has a future before it 
of which inventors will do well to take heed : — 
M. Georges Fournier, of Paris, has devised a method for ob- 
taining sodium sulphate, commonly known as Glauber’s salt, 
depending on this novel industrial agency : — In various parts of 
France, especially in the neighbourhood of Rheims and in 
Picardy, there occur extensive deposits of pyritic shales far too 
poor in sulphur for use in the kilns of sulphuric acid works, and 
only occasionally utilised in the manufacture of copperas and of 
alum. But now the latter product is generally prepared from 
china clay, or from bauxite, and now the works at La Tolfa 
have been revived by means of French capital, and are sending 
to France and elsewhere large quantities of the much esteemed 
ti Roman alum,” the makers of alum from pyritic shales— despite 
the cheapness of their raw material — find themselves driven out 
of the market. 
The problem, then, which M. Fournier undertook to solve is 
this :— How are such shales to be utilised, and especially how 
can the sulphur which they contain be made to effect the 
decomposition of common salt and the produftion of sodium 
sulphate ? 
