i6 4 ANALYSIS OF L1TITOMARG2. 



turnfole, arc a little aftefled by thefc vapours? 

 tlie firll becoming ycllowilh, the other inclin- 

 ing to reel ; thus indicating the prefence of a 

 very weak acid. While the fund that iurrounds 

 the vcilel approaches to a red heat, the powder 

 within uiTunics a black colour ; but as the firt* 

 vncreafcs, thi> oblVwity gives way, and the. ori- 

 ginal colour returns. From this appearance of 

 black, and itsfubfequent deltrudion by the lire, 

 it might- be fuppolcd, that ionic oily fubftanco 

 was contained in the powder, which being firlt 

 reduced to a coal, was again confumed by a 

 greater heat. After tho opcrat ion was finiihed, 

 and the powder cooled, it was found to have loft 

 17 per cent, of its weight. 



A fmall piece of this earth placed upon char- 

 coal, and expofed to the ilume of a blow-pipe, 

 does not decrepitate, but turns black, melt J 

 with ebullition, and is converted into a dark 

 frothy cinder. Willi the microcofmic fait, it 

 dcfolves partially at lirlt, and with eflfcrvefce nee; 

 but afterwards, the remainder is fcarcely dimin- 

 illied. Borax acts moil etleftually upon there- 

 iiduum, but it is fome time before the whole is 

 confumed. The fait of foda occufit-ns a conli- 

 derable eilervefcence with noile. Henco, then, 

 it would appear to contain a portion of aerated 

 earth, 'though the greatefl part of it i* filiceous. 

 The little glais globules are tinged in the (liglit- 

 cil degree with a colouring of iron. 



> When 



