/nalyfu of a M'meral front New South IValcs. ■ 407 



Tn all the «per!ments of diffolution, as often as the heat was at or near the boiling 

 point of the acid, frequent and pretty fingular burfts or explofions happened, though the 

 niatter lay very thin in a broad-bottomed glafs. They were fometimes fo confiderable as to 

 throw off a porcelain c^.^^^ with which the glafs was covered, and once to (hatter the glafs in 

 pieces. In a heat a little below this, the cxtraftion feemed to be equally complete, though 

 iTTore flow ; but a heat a little below that in which wax melts, or below 140° of Fahrenheit's 

 thermometer, appeared infufficient. 



To determine the degree of folution necefTary for the precipitation of the diflblved fub- 

 ftance, and whether the precipitation by water be total, a meafi.re of the folution was poured 

 into a large glafs, and the fame meafure of water added repeatedly. The third addition of 

 water occafioned a flight milkinefs, which increafed more and more to the fixth. The 

 hquor being then filtered off, another meafure of writer produced a little frefh milkinefs, and 

 an eighth rather increafed it ; a ninth and a tenth had no effea. The liquor being now 

 again paiTed through a filter, folution of fait of tartar did not in the lead alter its tranfparency 

 fo that after the folution has been diluted with eight or nine times its meafure of water' 

 there is nothing left in it that alkali can precipitate. ' 



From the manner in which the folution is necefTarily prepared, it cannot but contain a 

 great redundance of acid; for the fmall quantity of acid fufficient for holding the foluble 

 part fufpended, would be foked up or entangled by the undiiTolved part, fo as fcarcely to 

 adm,t of any being poured o(f ; and it cannot be diluted or waflied out but by the flrong 

 acid itfelf. The folution with which the above experiment was made, was reckoned to 

 have only about fix grains of the foluble matter to three ounces of fpirit of fait, having been 

 prepared by digefting that quantity of the fpirit, by half an ounce at a time, on thirty grains 

 of the crude mineral. 



A faturated folution was obtained by digefting, on a.fmall portion of the folutions thus 

 prepared, the precipitate thrown down by water from the larger portions till the acid would 

 take up no more. A folution thus faturated cannot bear the fmalleft quantity of water- a 

 fingle drop, on the firft contafl, producing a milky circle round it. ' 



Examination of the above Sulfa„ce, e>:traaed from the Mineral by Marine Add, and precipitated: 



hy Water. 



THIS fubflance wafhed and dried is indilToIuble in water, as indeed might be expefted 

 from the manner of its preparation. 



Nor is it aded upon by the nitrous or vitriolic acids, concentrated or diluted cold or- 

 hot, nor by alkaline folutions, mild or cauflic, of the volatile or fixed kind. 



It is diflblved by ftrong marine acid, but not without the afhttance of nearly the fame de 

 gree of heat that is neccifary for its extradion from the mineral. From this folution it is ■ 

 precipitated by water; and after repeated diflblutions and precipitations it appears to have 

 fuffercd no dccompofition or change. 



Spirit of nitre, added to the faturated folution, makes no precipitation ; and if tlie quan 

 tity of nitrous acid exceeds, or at lead does not fall much (hort of, that of marine acid in 

 the folution, the mixture fufiers no precipitation from water. Nor docs any precipitation \ 



happen, , 



