CHEMICAL EXPERIMENTS. 299 



three months. The produce during this time was converted 

 into a black brilliant powder. On attempting to collecx it 

 together into one heap, and feparating it from the paper which 

 had been interpofed, a globule of running mercury was feen. 

 On introducing the powder into a bottle, and (baking it to- 

 gether, heat was evolved, and the whole mafs became re- 

 duced to the metallic ftate. 



12. Production of red Sulphuret of Mercury in the humid Way. 



When equal quantities of a concentrated folution of oxigen- Cinnabar in the 

 ated muriate of mercury, and concentrated frefti prepare^ umid way * 

 fuming hidrofulphuret of ammonia, are mingled together, a 

 brownilh muddy precipitate is produced, which, when left 

 undifturbed, turns yellow in three or four days, then orange, 

 and at laft acquires a beautiful cinnabar-red colour. The ful- 

 phuret of mercury, when feparated, poffbfles all the properties 

 of the beft vermilion which is met with in commerce. 



13. Air Bladder of the Carp contains conunon Air. 



The air bladder of the carp does not contain nitrogen, as Error of Four- 

 Fourcroy, &c. affert. If the air of the bladder of this living '™^ oncernin « 

 fifti be examined, it will be found to contain atmofpheric air, 

 and not nitrogen. 



1 4. Fifh Bones contain much phofphoric Acid. 



The bones of fifh contain upwards of one fixth part more Fi/h bones 

 of phofphoric acid, than thofe of quadrupeds. They may a j£f n £^j th 

 therefore advantageoufly be employed for making phofphorus. 



1 5 . Wax from Spiders. 



The yellow matter depofilcd in veflels containing fpiders Spiders' wax. 

 preferved in alcohol, is a true wax, which may be obtained 

 from thefe animals by gently heating them. 



16. Fluoric Acid diffolves Lead. — Method of obtaining it pure. 



Fluoric acid obtained in the ufual manner, by decompofing Common fluoric 

 filiate of lime by fulphuric acid in a leaden retort, always con-. aci ? containa 

 tains lead in folution ; as may be proved by mingling the acid 

 with a folution of water impregnated with fulphurated hidro- 

 gen gas. Tin vefTels are lefs acted upon than thofe made of 

 lead. The acid has no effect upon filver. 



In 



