573 
Ca^t Iron^ Steely and Malleable Iron, 
matter was deposited, traversed by beautiful red needle-like 
crystals ; these crystals washed with water during solution lost 
their colour, were not soluble in alcohol, and heated in a glass 
tube emitted a very pungent smell somewhat resembling cya- 
nogen. 
The liquid solution of nitrate of lead smelt very strongly of 
hydrogen developed from cast iron, and I am convinced, that 
this compound of hydrogen, carbon, azote, and sulphur forms 
a salt with the oxide of lead, which is more distinct, when the 
acid, in which the cast iron is dissolved, is so weak, that little 
or no sulphuretted hydrogen is disengaged. When acetate 
of lead is used, and the lead carefully precipitated by sul- 
phuric acid, this compound is separated from the lead and will 
be found to swim on the surface of the liquid. It is unfortu- 
nately too little to be collected, and the only way to glean some 
idea as to its composition is, to detonate the hydrogen with 
oxygen *. 
Another remarkable circumstance is, that in determining 
the quantity of arsenic contained in the iron by boiling it in 
aqua-regia, dropping the neutralized filtered liquid into hydro- 
sulphuret of ammonia, and decomposing it carefully with acid, 
the precipitated sulphur, during its solution in aqua-regia, de- 
posited invariably a black scaly heavy substance, darker than 
graphite. From 12*89 grains of this sulphur, I separated 
0*36 grains of these black scales. By heating them in a glass 
tube, sulphur was disengaged, and black dull scales re- 
mained equal to 0*1438 grains. These black scales were not 
soluble in any acid, and appeared through the microscope 
mixed with white transparent grains. A part of these scales 
heated on a platinum foil began to sparkle, glowed in a very 
lively manner, which after some time ceased, and a white 
powder remained, mixed with those transparent grains. The 
powder before the blowpipe appeared like silica, and the scales 
consisted therefore probably of sulphuret of silicon, or a mix- 
ture of sulphuret of silicon with metallic silicon ; or it might 
perhaps be considered as a compound of sulphur, carbon, and 
silicon. If we consider it as a simple sulphuret of silicon, we 
6 
might obtain the not very probable formula Si S. 
* A series of experiments, which I have made recently, and since the 
writing of the above paper (which only contains the experiments made 
while travelling through England and France), confirm entirely this opi- 
nion. I shall elucidate this subject further in a paper on the gases deve- 
loped by treating iron with acids, and describe at the same time a new 
portable apparatus for analysing the compound radicals (of organic che- 
mistry), by means of which the oxygen, hydrogen, carbon, and azote of 
the compound are easily determined in one operation only. 
