SCIENTIFIC SUMMARY. 
123 
remove the contained salts, and magnesium, more or less pure, remains 
behind. Mr. Sonstadt directs that the metal thus produced be immediately 
dried at a temperature of 212° Fahr., and purified by fusion in anhydrous 
chloride of magnesium. 
Preparation of Antimony.- — The sulphide of this metal is thrown upon 
a furnace so arranged that the fumes proceeding therefrom are allowed 
to mix with the air and are collected in condensers. The vaporised 
sulphide is decomposed, the sulphur passing off as sulphurous acid, 
whilst the oxide is deposited upon the surface of the condensers, The 
metal is abstracted from the oxygen compound, by being mixed. with 
carbonaceous and alkaline matters and smelted in a furnace constructed 
for the purpose. The above process has been patented by Mr. B. Todd of 
Falmouth. 
State of Carbon in Cast Iron. — This is the subject of a very interesting 
communication by Mr. Crossley to the Chemical News of July 25th. 
The author objects to the views generally received relative to the con- 
dition of carbon in cast-iron. He believes that it is always in chemical 
combination and never mechanically mixed with the metal ; and selecting 
grey iron as an example of what is supposed to contain graphite uncom- 
bined, he adduces the following arguments in support of his views: — 1. 
Grey and white iron contain the same per-centage of carbon ; when the 
former is melted the graphite is admittedly in solution, yet on cooling it is 
deposited. (?) Such is not the case with white iron ; why should this be, 
when we know that both contain the same quantity of the carbon (4 per 
cent.), and that, as Faraday has shown, iron is capable of combining 
with 6’00 per cent, of this element? 2. When a little sulphide of iron is 
added to melted grey iron, graphite is instantly liberated, thus implying 
the existence of a chemical rather than a mechanical combination. 3. 
When grey iron is acted on by acids, carbon is lost in the form of volatile 
carbides of hydrogen, an oily matter being simultaneously developed. 4. 
By exposing a bar of wrought iron to a high temperature and allowing a 
current of coal-gas to play upon it, it is gradually converted into grey iron; 
if grey iron contains solid flakes of graphite, how can they possibly enter 
the bar under these circumstances ? Mr. Crossley explains the differences 
in physical aspect between white and grey iron, on the supposition that 
both varieties are carbides of iron mixed with the pure metal, manganese, 
silicium, calcium, &c., and that the grey is a higher carbide than the 
white. 
Purification of Copper. — It has been found that iron is almost invariably 
present in all copper, and that even cupric salts are not free from traces of 
the chalybeate, whose presence accounts for the greenish tinge of certain 
compounds of this metal. An excellent process which has been devised by 
MM. Millon and Commaille for the complete purification of copper, is as 
follows : — The metallic copper is treated with commercial sulphuric acid 
which has been diluted with half its volume of water ; it is then boiled 
till sulphurous acid ceases to be disengaged and till all the copper is dis- 
solved. The copper which is crystallized from this solution does not 
contain arsenic, although the latter may have been present in the sulphuric 
acid ; but it almost always contains iron, and not unfrequently zinc also. 
