Analysis of S(o7ie<r. • jQj 



daHy if 3 small quantity of the mass, when dissolved in 

 •water, communicates to that fluid the same colour. If the 

 mass is of a yellowish green, the oxide of chrome may be 

 present. 



II. When the mass has been thoroughly fused or kept 

 in a red heat for at least two hours, remove the crucible out 

 of the fire, and \\hen nearly cold pour water into it o-radu- 

 ally, in order to detach the mass from the crucible 9 transfer 

 the whole into a flask, pour four limes its quantity, or more 

 of water over it ; boil the mi.xture for about half an hour, 

 and then suffer it to subside. 



III. Having done this, pour gradually muriatic acid into 

 the before obtained solution without previously separatini^ 

 the insoluble part, if any. Ilie first portion of' acid which 

 is added occasions a flocculent precipitate, then aii effer- 

 vescence takes place, and a cojxous precipitate immediately 

 follows; which, however, is no sooner formed than it is 

 redissolved. On adciing more acid, the portion of the nias>- 

 which resisted the action of water, and m hich was not dis- 

 solved in Process II., will become dissolved. If it consists 

 of alumine it will be taken up silently by the acid ; if it be 

 lime, barytes, or strontia, it will be dissolvcti with eficr- 

 vcscence. 



lieinark.— From the plu-snomcna attending the process 

 of the solution of this mass in muriatic acid, some mdica- 

 tions may be derived. If the solution be colourless the 

 stone contains no metallic substance, or only a minute 

 quantity. If its colour be purpleish red, it contains man- 

 ganese; orange red is a sign of oxide of iron; gold yellow 

 bhows chrome- 



IV'. To separate the different earths. Sec. contained in the 

 solution, e\aporatc it to dryness; when the evaporation is 

 approaching towards its completion it assumes a gelatinous 

 appearance, it must then be diligently stirred with a glass 

 rod till it is almost dry. 



\^ Transfer the mass into a large quantity of water, boil 

 the mixture for a few minutes aiid then filter it, wash the 

 insoluble residue left on the filter repeatedly, dry it and ex- 

 pose it to a red heat ; its weight shows the quantity of silex 

 contained in the stone. If i't is pure silex it will be pcr- 

 lectly white, entirely insoluble in sulphuric, nitric, and 

 muriatic acids : if it be coloured it is contaminated with ■ 

 ^ome metallic oxide, and shows that th<: evaporation t(j dry- 

 ness has been performed with too much heat. From the 

 metallic oxide it may be purified by digestion in muriatic 

 acid, and, then wa.siic'd and dried as'beiorc, 'I'hc acid ex- 

 pended 



