431 
Cast Iron^ Steel, and Malleable Iron. 
grains in weight during ignition, we may conclude, that the 
black spots consisted of metallic silicon, which had become 
oxidized into silica during the process. 
The solution had a greenish-yellow appearance, and after 
being concentrated by evaporation and diluted with distilled 
water was mixed with carbonate of magnesia. The precipi- 
tate dissolved in hydrochloric acid and again precipitated 
with succinate of ammonia, yielded 2*50 oxide of iron = 
1*7335 metallic iron ; no manganese could be discovered. 
The filtered liquid now held in solution the protoxide of 
iron. Digested with nitric acid, precipitated with ammonia, 
ignited, dissolved again and freed from magnesia, it yielded 
oxide of iron = 1*100 = 0*8901 metallic iron. This method 
of separating the protoxide of iron from the peroxide is not 
sufficiently accurate, and I mention this part of the process 
only to show that the iron, even after ignition, remained in 
the state of protoxide mixed with peroxide. Having tried 
to ascertain the amount of protoxide and peroxide of iron in 
these solutions as accurately as possible, by converting the 
peroxide of iron by means of solution of sulphuretted hydro- 
gen into protoxide, and ascertaining the quantity of separated 
sulphur &c. in one part of the solution, and mixing another 
part with liquid chloride of gold and sodium, — from the quan- 
tity of the reduced gold the quantity of protoxide of iron was 
very easily calculated, and I obtained for the greatest part 
proportions which approached to a rather strange formula, 
3 F + 2 F. The carbon taken away by the escaping hydrogen is 
of far less amount than is generally asserted ; and each atom 
of carbon volatilized in this way is at the same time replaced 
by oxygen or sometimes hydrogen. 
The remaining part of the brown powder, = 3*39, was like- 
wise put into a platinum crucible, heated like the first over 
a spirit lamp, till it began to glow on the periphery, and then 
quickly removed from the fire. The first smooth surface of 
the powder on the bottom of the crucible was now found to 
be intersected by small cracks, through which might be seen 
the interior of the powder in ignition for some time ; its colour 
after cooling became darker, but it had neither gained nor 
lost in weight. 
Hydrochloric acid of 1*16 sp. gr. did not visibly attack 
this powder; but heated in a sand b^ath, the action of the acid 
became at once very lively; a great quantity of hydrogen 
smelling slightly in the well-known way was disengaged, and 
a velvety black residuum of a rather oily appearance was 
left. 
