*58 Mr. Smithson on a saline Substance 



V 



c. The masses of this salt are perfectly irregular, their tex- 

 ture compact, their colour a clouded mixture of white, of the 

 green of copper, and of a rusty yellow, and in some places 

 are specks and streaks of black. 



d. A fragment melted on the charcoal at the blow-pipe 

 formed hepar sulphuris. 



e. A piece weighing ^^5 grains was so strongly heated in a 

 platina crucible, that it melted and flowed level over the bottom 

 of it, but did not lose the least weight. 



y. Not the slightest fume could be perceived on holding a 

 glass tube wetted with marine acid over some of this salt, 

 while triturating in a mortar with liquid potash ; but a similar 

 mixture being made in a bottle, and which was immediately 

 closed with a cork, to which was fixed a bit of reddened lit- 

 mus paper, the blue colour of the paper was restored. 



g. Being dissolved in water, there was a small sandy resi- 

 due, which consisted of green particles of a cupreous nature, 

 of a yellow ochraceous powder, and of minute crystals of a 

 metallic aspect of red oxyd of iron, by which the black spots 

 in the mass had been occasioned.* Mr. Klaproth found a 

 similar admixture in muriate of soda from Vesuvius.-f 



h. The solution had a feeble green tint. It did not alter 

 blue or reddened turnsol paper. 



i, Prussiate of soda-and-iron threw down a small quantity 

 of red prussiate of copper from it Liver of sulphur and tinc- 

 ture of galls likewise caused very small precipitations. 



* What mineralogists denominate speculary iron ore, Fer oligiste of Mr. Hauy, 

 appears to be merely red oxyd of iron in crystals ; red hematite the same substance 

 in the state of stalactite ; and red ochres the same in a pulverulent form. The he- 

 matites which afford a yellow powder are hydrates of iron. 



t Essays, Vol. II. p. 67, Eng. Trans. 



