Dr. Schafhaeutl on the Different Species of Cast Iron^ ^c. 571 
contains more sulphur than the quantity mentioned by him. 
Charcoal itself imparts a portion of sulphur to the iron. 
As a further proof of what has just been asserted, we now 
refer to some specimens of French cast iron, the produce of 
the furnaces near Alais, departement du Gard, at the foot of 
the Cevennes. 
These specimens were produced from hydrated oxides of 
iron, which cover the summits of several hills of limestone and 
carboniferous sandstone extending over a long district, and 
have undoubtedly been deposited in this state by water. The 
greatest part of this ore has a perfectly ochry appearance, in- 
termixed with masses of red oxide of iron, which is so similar to 
oxide of iron, precipitated from its solution in acids by caustic 
ammonia, and dried on a filter, that it is impossible to distin- 
guish between the two specimens when placed together, which 
is the artificial and which the natural. As it is the mode in 
France to assay the iron ores only in the dry way in a small 
crucible, lined with charcoal, nothing more is obtained than the 
quantity of metallic iron which is contained in the ore ; and as 
those ores were found to be very rich and in great abundance, 
a large iron-work has in consequence been erected; but actual 
trial of the ore in the blast furnaces very soon convinced the 
proprietors, that in the selection of ore for practical purposes 
more research is I’equired than the mere melting down of three 
grammes of iron ore in the crucible in the laboratory. 
The iron obtained from this ore had invariably the bad 
quality of emitting a great quantity of fumes during heating, 
and not welding except in a state of half-fusion. But when 
this welding was accomplished, the iron naturally had lost its 
quality, and was found to be burnt. This ore is invariably 
mixed with a subarseniate of iron, which contains in 100 parts 
7 of arsenic acid and 13’68 of water, and is mechanically mixed 
with galena, bournonite, and similar minerals. The small 
quantity of arsenic in this case is easily overlooked even with 
the blow-pipe, and generally no other means will detect the 
presence of arsenic except a current of sulphuretted hydrogen. 
The manner of conducting the blast furnaces with pit coal 
in France is, notwithstanding the great difference in the ores, 
exactly the same as in England ; and English workmen are 
down to the present time generally employed, not only in work- 
ing at the puddling furnaces, but also at the blast furnaces. 
It will be apparent, that the above-mentioned ore is ex- 
tremely fusible, and requires therefore a very careful arrange- 
ment of the fluxes, in order to obtain a tolerably good quality 
of cast iron, particularly as in this hot southern climate the 
rarefied and dry air has a peculiar influence on the produc- 
2 Q 2 
