3 10 Seyhert^s Analysis of the Maclunite. 



silver crucible wi(h nine grammes of caustic potash ; when 

 the matter had cooled, It was treated with water, and (he 

 sohjtion was filtered, the filtered liquor was supersaturated 

 with muriatic acid, the sohition was treated with an excess 

 ofammonia, this produced a gelatinous precipitate, which 



s separated hy filtration, t!ie iillcred liquor was again 

 treated with a slight excess of muriatic acid, and boiled to 

 expel the carbonic acid, it was then exactly neutralized 

 with ammonia, and treated with lime water, no precipitate 

 was formed, audit was treated with murialo of lime with 

 the same result ; these experiujents induced me to believe, 

 that the mineral in question contained no fluoric acid, 

 nevertheless, to reduce this fact to greatercertitnde,! follow- 

 ed precisely the method employed by Professor K]aproth,iu 

 his analysis of the PyCnite, viz. three grammes of the sub- 

 stance, reduced to a fine powder, were calcined in a sil- 

 ver crucible, with caustic potash, the silica was separated 

 in the usual w^ay, the liquor w^as treated with an excess of 

 gubcarbonate of soda, to precipitate the Magnesia; after 

 filtration the carbonic ncid was expelled, from the liqtior, 

 by an excess of muriatic acid and subsequent cbullitioru it 

 was then exactly neutralized with ammonia, and treated 

 with a solution of pure lime and muriate of lime, without 

 ?iay precipitate having been produced by these reagents. 



My attempts to discover Fluoric acid having thus proved 

 fruitless, 1 determined to direct my attention to the ap- 

 pearances which occurred during the calcination of the si- 

 lica in the two preceding analyses, the sublimate was ver}' 

 minute in quantity, I prepared some of it from silica ob- 

 tained, from the mineral, as in the preceding analyses. I'he 

 silica was dried, at a modernte temperature, and then ex-^ 

 posed to a red heat, in a small glass retort; before the 

 glass was reddt ned, there passed over a small quantity of 

 water, and a white sublimate appeared on the dome of the 

 retort ; as the heat increased, this sublimate descended 

 into the neck, and lastly, partially, into a receiver adapted 

 to condense it. After the calcination, the retort was re- 

 moved from the fire, the receiver contained orly a very 

 small portion of the sublimate, and a vapour possessing a 

 a very pungent odour, which reddened litmus with great 

 energy: the sublimate incrusting the neck of the retort 

 svas colourless, and very acid to the ta.-te. in water it dis- 

 solved partially, leaving a flakv residue, the liquor became 



