/roTTi the River Dee, in Alerdeenshire. ,101 



Black oxide of iron, - 98*70 



White oxide of titanium, 12*65 



Arsenic, * - - i 'OO 



Silica and alunmina, - 1'30 



Total, 113-85 



Here there is an excess of nearly 14 grains, owing, without 

 doubt, to the combination of oxygen with the iron and the 

 titanium during the analysis. 



Had the iron in the ore been in the metallic state, the 

 excess of weight, instead of 14, could not have been less 

 than 30. For the black oxide is known to be a compovmd 

 of 100 metal and 37 oxygen. Hence, I think, it follows, 

 that the iron in our ore must have been in the state of an 

 oxide, and that it must have contained less oxygen than 

 black oxide of iron. A guod many trials, both on iron- 

 sand, and on some of the other magnetic ores of iron, in- 

 duce me to conclude, that the iron in most of them is com- 

 bined with between 17 and 18 percent, of oxygen. This 

 compound, hitherto almost overlooked by chemists, I con- 

 sider as the real protoxide of iron. Thenard has lately de- 

 monstrated the existence of an oxide intermediate between 

 the black and the red ; so that we are now acquainted \vii]i 

 four oxides of this metal. But the protoxide, I presume, 

 does not combine with acids like the others. Analogy leads 

 us to presume the existence of a fifth oxide, between the 

 green and the red. 



' As to the titanium, it is impossible to know what in- 

 crease of weight it has sustained, because we are neither 

 acquainted with it in the metallic state, nor know how 

 much oxygen its different oxides contain. It is highly im- 

 probable, that, in iron-sand, the titanium is in the metallic 

 state, if it be made out that the iron is in that of an oxide. 

 The experiments of Vauquelin and llecht, compared with 

 those of Klaproth, have taught us thar there are three oxides 

 of titanium, namely, the blue, the red, and the white. 

 From an experiment of Vauquelin and Hecht, and from 

 some of my own, I am disposed to consider these oxides as 

 composed of the following proportions of metal and oxygen : 



Metal. Oxygen. 



1. Blue, 100 \Q 



2. Red, 100 33 



3. White, 100 49 



I find, that when the white oxide of titanium is reduced ta 



G3 the 



