Volltext Seite (XML)
482 Third Appendix. dered; if yellowifh, it probably contains iron,- and no other, or but little of any other metallic fubftance; if brownifh, probably manganefe if greenifh, poffibly nickel, or copper; if bluifh, copper. 92. To diflinguifh whether the greenifh colour proceeds from nickel, or copper, fuperfaturate a portion of the folution with cauftic volatile al kali •, if a blue colour does not arile, the colour muft be from iron; but if the colour changes blue, it muft be from copper, or nickel; if from copper, a clean polifhed iron will preeipitate. the copper, but, if from nickel, it will be of no ef- fe£t; befides, the calx of nickel will recover its greenifh colour as foon as the volatile alkali is exhaled, whereas that of copper will not. 93. If the folution contains no other metallic fubltance, but iron, or iron and manganefe, we may preeipitate thefe by cauftic volatile alkali ; the preeipitate filtred, wafhed, and heated ta rednefs, fhould be repeatedly treated with nitrous- acid, evaporated to drynefs until the calces be- come thoroughly oxygenated, and, finally, the argill and nragnefia that may exift in the preci- pitate are to be re-diffolved, and feparated from the metallic calces by dilute nitrous acid, and from each other, as flrewn from No. 19 to 29, inclufively. 94. The calces of iron :.:id manganefe are next to be feparated; to eff'edt this, let them be boiled in a concentrated lye of caullic vegetable alkali, which will take up the manganefe, and not the iron; or let them be well mixed with eight or ten times their weight of pulveri/.ed nitre thrown into a crucible, and kept in fufion for one hour; pour the meltcd mafs on a flone flab, leaving the iron