,S04 Dr. Schafhaeutl on the Different Species of Cast Iron^ S^c, 
= 7*08 grains. The same quantity of the same iron treated, 
in the above-mentioned manner with nitric acid of ITO spe- 
cific gravity left residuum grains ; no trace of sulphuric 
acid could be discovered in the liquid. By boiling the re- 
mainder in a platinum crucible with strong nitric acid, the 
greatest part of the sulphur was separated, which adhered 
slightly as a yellow riband to the side of the crucible, and no 
traces of sulphuric acid were to be found in the solution. The 
sulphur thus separated from 1*55 grains of the residuum 
weighed 0-180 grains, and this burnt on a platinum foil left 
0*100 sulphuret of iron. That which the nitric acid had 
dissolved during the boiling was precipitated with caustic 
ammonia and consisted of 
Iron 0*4<43 
Phosphorus . . . 0155 
And left residuum .0*31 
Humine .... 0*33 
We see therefore that the sulphur had been in combina- 
tion with the iron, approaching in this formula S, that is in 
a certain well-known state of chemical proportions. 
Another remarkable circumstance is the difference of the 
products of solution according to the difference of the specific 
gravity of the acid, which throws a light on several chemical 
products, which arise from different degrees of concentration 
of chemical agents, and the varying products obtained by the 
various degrees of heat. 
In hydrochloric acid we have a juxtaposition of atoms of 
chlorine and hydrogen intermixed with atoms of hydrogen 
and oxygen ; and the interposition of a certain quantity of 
atoms of water betwixt a certain number of atoms of chlorine 
and hydrogen, alone determines how many atoms of the iron 
shall combine with chlorine to form protochloride of iron, and 
how many atoms of hydrogen shall form compounds with car- 
bon and azote. 
The description of the residuums left by treating iron with 
acid w-as always a matter of great speculation. Berzelius 
says the remainder of the solution of iron in sulphuric acid 
was black, in hydrochloric acid gray, and sometimes white._ 
The colour of the residuum, as shown, depends partly on^ 
the specific gravity of the iron and partly on its chemical: 
composition. 
The residuum of white cast iron prepared with coke as 
fuel, in hydrochloric acid is always brown, yellowish brown 
or greenish brown ; the remainder of very gray coke iron is 
always light gray, in different shades approaching to white. 
[To be continued.] 
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