Redu&m and Properties of the New Metal Chromct 4jf3 



SECTION VII. 



ReduStlon of the Add of Red Lead to the Metallic State. 



THOUGH the properties of the acid of red lead, defcribed in the foregoing paragraphs, 

 are in flri£lnefs fuflicient to convince thofe who are in the habit of treating metallic fub- 

 ftances, that this fubftance belongs to the fame clafs, it is neverthelefs defirable, in order, as 

 it were, to add the ftamp of evidence to the proofs of demonflration, that this acid ftiould 

 be reduced to the metallic ftate. 



To obtain this obje£l I took 72 parts of the acid in queftion, extracted from the red lead 

 by the muriatic acid, as defcribed in our fourth fedlion, wbicli I introduced into a crucible- 

 of charcoal placed in another of hard porcelain likewife filled with charcoal powder. 



This apparatus, placed in a forge furnace, was expofed for an hour to the a£tion of a 

 very flrong fire urged by the blafl of a (Irong pair of bellows with three pipes. 



Wlien the crucible was cooled and broken, I found, to my great fatisfadion, in the fmall 

 veflel of charcoal, a metallic mafs of a white grey colour, fliining, very brittle, and upon 

 the furface of which were many feathered cryftals of the fame colour pcrfedlly metallic* 

 This metallic mafs weighed forty-three parts. 



It appears, from the refult of this operation, that the oxygen does not adhere with very 

 great force to this metallic bafe, and that the acid contains about 0,4.0 of its weight of this 

 acidifying principle. 



SECTION VIII. 



Properties of the Metal of Red Lead. 



THIS metal, as I have already remarked, is of a white colour inclining to grey : It is very 

 brittle, and cryftallifes in an elevated temperature into a kind of feathered filaments, which, 

 rife above the metallic mafs. 



The metallic button being broken, prefented internally compafl points forming a clofe 

 grain, and in other parts needles crofiing each other in all dire£lions, leaving void fpaces 

 between them, which prevented me from determining its fpecific gravity. 



A fragment of this metal expofed to the heat of the blow-pipe acquired a tarnifh on its 

 furface, and by continuing the operation it was covered with a light green cruft ; but it af- 

 forded no fign of fufion. 



When heated by the fame apparatus with borax it did not melt, but was in a fmall de- 

 gree diminiflied, and communicated an emerald- green colour to the fait. 



When reduced to a fine powder, and treated with the concentrated boiling nitric acid,, 

 it was oxided with much difficulty, and communicated to the acid a green tinge flightly. 

 inclining to blue. The nitric acid attacks this metal with fo much difficulty, that it wa* 

 not till after treating it repeatedly with conliderable quantities of that folvent that I could; 

 fucceed in diflblving fix grains. 



The diflTerent folutions being added together were evaporated to drynefs. Towards the 

 end of the operation the refidue aflumed the form and the du£lility of a vegetable extraft 

 of a red brown colour. Cauftic potafli poured on this refidue diflblved a great part, and 

 aflumed a lemon-yellow colour ; but part remained of a very beautiful green, which wa« 

 apt afted upon by that re-agent : it was a portion of the metal which had not received. 



4 fxoiftj 



