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AnaijJls. 481 arglll, alfo taken up by the alkali, often thus is depofited. The neutralized liquor fhould then be filtred, the depofit vvaflied, and dried, and the filtred liquor effayed for vitriolic acid, as in No. 37. 88. The depofites, No. 87, may confift of fi- lex and argill, which are beft feparatedby boiling in the vitriolic acid, and precipitating the folu- tion by mild volatile alkali ; the argill thus found, to be dried, heated to rednels for half an hour, and weighed, or effayed, for jargonia, as already mentioned; the filex alfo to be heated, and weighed, as before fhewn. , 89. We now proceed to the filtred mafs, No. 86 i this may confift of mild calx, ftronthian, barytes, magnefia, argill, jargonia, adamantine, befides fome remains of filex, with calces of iron, manganefe, or nickel, or fome undecompofed part of the original ftone. 90. To feparate thefe, or as rnany of them as , cxift in the ftone, treat the whole with aqua re- ' gia, formed of two parts marine, and one part nitrous acid, in a retort, and boiling heat, re- peatedly cohobating, or adding frefh acid, until the whole, or nearly the whole, if poffible, is difi'olved ; what efcapes folution may be either filex or adamantine, which may be decided by its fufibility or infufibility with fixed alkalis. lf Sydneia be fufpedted, it may be difcovered by its folution in pure marine acid, precipitation by water, and ocher tefts of that earth. lf any con- fiderable part of the ftone has efcaped decompo- fition, it fhould again be torrefied with fixed al kalis. 01. The foluble earths being thus held in fo- lution, the colour of the folution is to be confi- 1 i dered j