, 132 ACCOUNT OF A MINL'RAL SUBSTANCE, 



heat, in a filver crucible. As foon as the matter began to fiW,- 



a very perceptible effervefcence took place ; and, when this 



had fubfided, the whole was poured into a proper vefTel. 



The mafs, when cold, was grayifh-brown. 



ferlefta brown" BoilJn S diftiIIed watcr was poured upon it ; and the brown 



refidue. refiduum, which wasconfiderable, was well edulcorated upon 



a filter. 



Predp. by ni- The filtrated liquor had a flight yellowifh tinge, and, being 



white flakes, fuperfaturated with nitric acid, afforded a copious white floe- 



culent precipitate, which fpeedily fubfided ; but, although a 



very coniiderable additional quantity of nitric acid was poured 



upon the precipitate, it was not re-diffolved. 



The refidue did The refiduum of the ore was dark brown, and was a^ain 



not yield to fu- . , / ° 



fion bypotafh. me'ted with potafli. and treated as before ; but fcarcely any 



effeel was thus produced ; the alkali was therefore warned off, 



It was therefore and the powder was digefted with muriatic acid, which foon 



mm-, acid* aflunied the deep yellow colour ufually communicated to it by 



which took up iron. After half an hour, the acid was decanted, and the 



,ron * refiduum was wathed with dift illed water. 



This refidue was This powder was now of a much paler colour : and, being 

 fufed with pot- , . , n . i , , , , / ? 



afh, and precipi- mixed with potafli, it was melted and treated as before. A 

 tated as before, coniiderable precipitate was again obtained by the addition of 

 What was left n ^" c ac *d > and ^ ie refiduum, after being digefted with mo- 

 was treated in riatic acid, was again fufed with potafli, by which means the 

 ner. man ~ wno * e was completely decompofed, after about five repetitions 

 of each operation. 



B. 

 The muriatic The muriatic folution was diluted, and, being faturated with 



te^wkii ^^o- amm o n » a > afforded a plentiful ochraceous precipitate ; which 

 nia afforded the again was diffolved in cold dilute nitric acid, and afforded a 

 fmall quantity of a white infoluble fubftance, fimilar to that 

 which was obtained from the alkaline folution. From thk 

 nitric folution, I then obtained, by means of ammonia, a pre- 

 cipitate of oxide of iron, which, being properly dried, weighed 

 40 grains. 



C. 

 The nitric pre- The different alkaline folutions which had been made fubfo 

 cipitates were a q Uen t to that which has been firft mentioned, were mixed to- 

 gether, and, being fuperfaturated with nitric acid, afforded 

 the fame white infoluble precipitate; the total quantity of 

 which, obtained from 200 grains of the ore, amounted to 

 •about 155 grains. 



The 



