Cast Irojiy Steel, 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 

 lamina 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 fruidess efforts, I finally discovered a new 

 method of decomposing them by means of acids, which gave 

 rise to new and interesting pheenomena. 



I poured about three fluid-drachms of concentrated sul- 

 phuric acid over two grains of these purified grai)hite 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 



