114 METALLIC StJLfHURKTS. 



are in the dally habit of prescribing ? I greatly fear that ii 

 may be much the fame with regard to its effects as with thofe 

 of fedative fait, and fo many other medicines, which have no- 

 thing to recommend them, but the honour which is done to 

 them, of affording them a place, from age to age, in our dif» . 

 penfatories and catalogues of the materia medica. 

 Mild muriate I iind alfo in my notes of the fame period, that the mild 



^huT-* WU U * nuir * ate > treated with fulphur in a retort, affords cinnabar and- 

 corrofive muriate ; the mild muriate is therefore divided into 

 two portions ; one of which is converted into cinnabar, and 

 the other charges itfelf with the oxigen and acid of the firft. 

 alfo turpeth. That turpeth mineral, treated in the fame manner, is 



changed into cinnabar, and quits the oxigen, which goes to 

 form fulphureous acid. 



The concentrated fulphuric acid decompofes cinnabar, like 

 the pyrites and other fulphurets, yielding to the metal they 

 oxigen which they require ; hence the fulphureous acid, &c. 



Cinnabar in the humid nay. 



Mercury prefer* Mercury having much more affinity for fulphur than for oxi- 



" P t gen, never fails to mew its preference for this combuftible. 



It is not fubjecc to the law which enables zinc, tin, antimony, 



&c. to combine w r ith fulphur, without abandoning the oxigen. 



Liquid fulphu- F. Hoffman was, I think, the firft who thought of decom- 



Wcrude'mer- P°^ in g tne ammoniacal fulphuret by means of mercury. 



curyj Baume and Wiegleb have lince occupied themfelves with 



the fubject, and in a more extenfive manner. 



Mercury, poured into flafks containing fulphuret of potafli, 

 or of ammonia, decompofes them entirely, and reduces them 

 which takes the to potam and ammonia : in the fpace of a few days it paffes 

 coiras 'cinnabar*. * I0m tne D ' ac ^ to tne re ^ colour. If mercury required oxigen 

 in order to affume the colour of cinnabar, whence mould it 

 take it ? This proceis is certainly of a very difoxidating na- 

 ture. 

 Mercurial falts ^he n ^ rates * muriates, fulphates, and mercurial oxides of 

 and oxides alfo. every kind, all yield aethiops in the firft moment of their mix- 

 ture with the fulphurets : they all become violently heated. 

 In order to accelerate their coloration, it will be fufficient to 

 place :he flafk with the mixture upon burning coals ; in an in- 

 ftant they begin to grow red at the points where the heat 

 exerts its aciion. Is it fulphurated hidrogen which they then 

 lofe r For my part, I cannot tell, 



AU 



