Oh Primary Ores of Iron \ $6$ 



I next expofed of this ore in fmall piees to a fimilar tem- 

 perature, in an open veflfel, - - 1804*2 grs. 

 After eight hours the fragments weighed * 2260 



Gained in weight, by the combination of oxygen, 455*8 grs. 

 equal to 25*2 per cent, of de-oxygenated ore, and to 19-6 of 

 raw ore. 



The magnetic virtue fo eminently manifefted in this 

 ore was now totally loft, and the individual pieces had ac- 

 quired a fenfible increafe of weight. From this ore I ob- 

 tained, by fufion, a button of oxygenated crude iron, equal 

 to 56'S 



Oxygen taken up, as above - ri*i 



Water of cryftallifation - - 11 '2 



Earths, chiefly filex and clay, - 12*2 



100 parts. 

 The fpecific gravity of this fpecimen I found to be — in a 

 raw ftate, 3*370; de-oxygenated, 3-060; ox ydated and com- 

 bined with 25 '2 per cent, oxygen, 4*000. 



Of the many experiments I have made upon the Cum- 

 berland iron-ore, the following, at the prefent time,, may 

 ferve as a comparative treatment with others. Of this ore, 

 pulverifed, I threw into a red hot veffel - 218*5 grs. 



Inftantly a blue flame arofe, and hovered nearly 

 half a minute upon the furface of the powder : 

 the fmell was fulphureous, penetrating, and 

 ftrong : the powder^ after 5 minutes, was taken 

 out, and weighed - - tH'S 



Loft of water and fulphuric acid 6 grs. 



The colour was confiderably deepened, and the mafs had ac- 

 quired a minute portion of magnetic obedience. 



I next torrefied, of this ore, in an open left, - 2086 grs. 

 After a bright heat of eight hours, the refidue 

 weighed - •• - - 1961 



Total lofs of water and fulphur - 125 grs. 



7 U 



