465 On phlogiston. 



attradion between the oxygen and metal is greater than 

 between the oxygen and the acid, the acid will not be oxy- 

 genated. This is the cafe with iron. 



A proof that the oxygenaticm of the muriatic acid, does 

 not depend merely upon the quantity of oxygen contained 

 in a calx is, that a drachm of manganefe, which has been 

 expofed feveral hours to a red heat, and parted with the 

 greateft part of its pure air, will oxygenate the muriatic 

 acid to a greater degree, than one ounce of mercurius ci- 

 nereus, or the calx obtained by boiling cauftic alkali upon 

 turbith mineral, which contain thirty times as much pure 

 •air. 



The Doctor likewife obferves, if finery cinder was iron 

 partially oxygenated, it would goon to attradt more oxy- 

 gen from the atmofphere, and in time be converted into a 

 rull of iron. 



In order to determine if finery cinder would attradl 

 oxygen, the focus of the lens was thrown upon a quanti- 

 ty of it, confined in pure air, which was not abforbed. 



The fteam of water was alfo pafled over it for feveral 

 hours, when red hot in an iron tube, but it fuffered no 

 alteration. 



One ounce of it reduced to a fine powder, was expofed 

 to the adtion of atmofpheric air upwards of twelve months, 

 and fprinkled with water feveral hundred times, and at 

 the end of this time, was as free from ruft, as when firfb 

 expofed, while an ounce of iron filings moiftened with 

 water, were covered with ruft in three days. 



I acknowledge that finery cinder cannot be converted 

 into ruft, but cannot lee in what manner this makes againft 

 the antiphlogiftic fyftem. When bar iron is converted in- 

 to finery cinder, it parts with the fmall quantity of coal it 

 contained, and abforbs oxygen and water. 



The ruft of iron differs from it materially, for it con- 

 tains a portion of carbonic acid, and although the French 



chemifts 



