5l8 Dr. Schafhaeutl on the Different Species of 
original state, viz. a dull red heat. After cooling it had as- 
sumed a light-gray colour, arising from the intermixture of 
black with white spots, some of the white spots had aggregated 
into rather large reddish-white lumps. It gained in weight 
= O’ 795 and was very powerfully attracted by the magnet. 
I boiled it again with concentrated hydrochloric acid and ob- 
tained a residuum = 4*217 grains. Heated on the lid of a 
platinum crucible it began to ignite spontaneously, and had 
afterwards lost 0* 1 24 grains. Its colour now assumed a lighter 
gray appearance, and it looked more woolly and voluminous. 
It was still attracted by the magnet. The black spots must 
therefore be a compound of carbon, iron and silicon, which 
could be destroyed neither by fire nor by acids. 
I weighed again 14*880 grains of the above-mentioned re- 
siduum, and boiled it with hydrochloric acid for nearly thirty 
minutes. The remainder of the powder weighed now only 
1'68 grains, was of a dirty yellowish-brown colour, and still re- 
tained the well-known smell of hydrogen gas. When heated 
it did not ignite spontaneously. It was apparently increasing 
in bulk, and began to assume a black colour, throwing up 
some dust on the sides of the crucible. After the crucible had 
acquired a white heat, the black colour rapidly disappeared, 
and a beautiful lemon-coloured powder remained, which after 
cooling, changed to a greenish yellow, and weighed T 12 grains. 
It consisted of 0*687 silica, and oxide of chromium and iron 
= 0*526. I mention these two experiments, to show the great 
difference betwixt the residuums of the two remainders, boiled 
for a shorter or longer time. The remainder loses its spon- 
taneous power of ignition the longer it is boiled in hydrochlo- 
ric acid, and the more iron that is extracted from it, not- 
withstanding the powder to a certain degree always retains 
the property of spontaneously igniting on the application of a 
certain heat, but the degree of temperature sufficient to cause 
this ignition rises higher the longer it is boiled. 
On being boiled for a short time only, and afterwards slowly 
ignited, the iron and perhaps silicon remain in a state of car- 
buret, which is unalterable either by heat or acids, and is 
powerfully attracted by the magnet. I mention here the 
curious circumstance, that when, in the above-mentioned 
remainder, which we found =• 1*68, we assume, instead of me- 
tallic iron, peroxide of iron, the loss is just equal to the quan- 
tity of carbon contained in 35 grains of iron. 
Oxide of iron . . 0*533 
Silicon .... 0*281 
Loss 0*866 
1*680 
