Cast Iron^ Steely and Malleable Iron, 589 
hydrochloric acid. The acid did not attack the crystal until 
heat was applied, and then quickly formed around the crystal 
a framework of white tough silica, apparently consisting of 
leaves or parallel threads, corresponding to the sides of the 
nucleus, which after having been separated from the silica 
with a fine needle, was finally converted entirely into a spot 
of silica. 
By repeatedly treating one of the large graphite layers or 
laminae with boiling hot hydrochloric acid and alkalies, it in- 
creased in blackness and brilliancy ; the single leaves ap- 
peared thinner, their mutual connection was loosened, and 
the magnet had no further action on them. 
With the exception of hydrofluoric acid no single chemical 
liquid seemed to have any action on those scales, and only the 
most concentrated hydrofluoric acid slowly attacked them, 
when in a state of most minute division. 
After several fruitless efforts, I finally discovered a new 
method of decomposing them by means of acids, which gave 
rise to new and interesting phsenomena. 
I poured about three fluid-drachms of concentrated sul- 
phuric acid over two grains of these purified graphite scales 
in a deep platinum crucible, and made the acid boil briskly 
over a spirit lamp. After this, I removed the crucible from 
the fire, till the dense fumes which arose began somewhat to 
cease. I then drew up about one fluid-drachm of strong 
fuming nitric acid into a long small glass tube, and dropped 
one half of the acid rather slowly, the other half quickly, into 
the hot sulphuric acid, which caused the latter to boil again, 
during a rapid evolution of binoxide of nitrogen. As soon as 
the boiling began to cease, I placed the crucible again over 
the lamp, and boiled the liquid till all the nitric acid was 
decomposed. I found the scales of graphite so much swollen 
as to fill up the whole lower part of the crucible, so that the 
liquid was no longer visible. On nearer inspection, I per- 
ceived that every single leaf of those scales was converted into 
a spongy body, of the lustre of coke, and of the same breadth 
and thickness, about the size of a pea. 
Washed with distilled water, and dried at 212° Fahr., those 
spongy masses weighed 2*18 grains, and lost after ignition 
0*39 grains. No degree of heat to be obtained by a large 
spirit lamp caused any further alteration. Their appearance 
in this state nearly resembled in lustre and texture pieces of 
hard coke and foliated charcoal ; they were composed of four 
to five easily separable layers, which were again intersected 
by several cracks or fissures vertical to them, similar some- 
what to the structure of charred wood, and their edges only 
