518 Dr. Schafhaeutl 07i 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 

 = 0795 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 1 • 1 2 grains. 

 It consisted of 0687 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 isjnition rises hio;her 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 ^^A 



Feso 



