588 PHILOSOPHICAL TRANSACTIONS. [aNNO 1795. 



noted 1 50'' of fire. The result was the same on treating oxide of steel, and of 

 iron, in the same manner as wootz. 



Concluiions. — Many of the properties of wootz, related in the preceding ex- 

 periments and observations, are so generally known to be those of the metallic 

 state of iron, that, but for the sake of order, I should think it superfluous to 

 refer to any of them particularly, to support the conclusion that wootz is at least 

 principally iron. Wootz is proved to be iron by the obvious properties (^ 2;) 

 by its filings being attracted by the magnet (§ 2.;) by its specific gravity {^ 2;) 

 by its affording nothing but sulfate of iron, hydrogen gaz, and a trifling re- 

 sidue, on solution in diluted sulphuric acid (^ ().) 



With regard to the particular state of iron, called wootz, I think I cannot 

 explain its nature satisfactorily, without first relating the properties, and explain- 

 ing the interior structure, of the principal different metallic states of iron. I 

 imagine I shall be best able to execute this design by stating precisely the just 

 meaning of the terms, which denote commonly the 3 principal metallic states 

 of iron, namely, wrought or forged iron, steel, and cast or raw iron. 1. Wrought 

 or furged iron, I understand to be that which possesses the following properties. 

 a. It is malleable and ductile in every temperature; and the more readily the 

 higher the temperature, b. It is susceptible of but little induration (and if 

 pure it is most probably susceptible of none at all) by immersing it, when ig- 

 nited, in a cold medium; as in water, fat, oil, mercury. Nor is it on the con- 

 trary susceptible of emoUition by igniting, and letting the fire be separated from 

 it very gradually, c. It cannot be melted, without addition; but it may be ren- 

 dered quite soft by fire, and in that soft state it is very tough and malleable. 

 d. It can easily be reduced to filings, e. By being surrounded with carbon for a 

 sufficient length of time, at a due temperature, it becomes steel, f. It does not 

 become black on its surface, but equally brown, by being wetted with liquid 

 muriatic and other acids, g. By solution in sulphuric and other acids, it affords 

 a residue of less than -j^ of its weight of carbon; and if it could be obtained 

 quite pure, there is no good reason to suppose there would be any residue 

 at all. 



2. Steel I understand to be that which has the following properties, a. It is 

 already, or may be rendered, so hard by immersion, when ignited, in a cold 

 medium, as to be unmalleable in the cold; to be brittle, and to perfectly resist 

 the file; also to cut glass, and afford sparks of fire on collision with flint, b. In 

 its hardened state, it may be rendered softer in various degrees (so as to be mal- 

 leable and ductile in the cold,) by ignition and cooling very gradually, c. It re- 

 quires upwards of 130° of fire of the scale of VVcdgvvooil's pyroii.eter to melt 

 it. d. Whether it had been hardened or not, it is malleable when ignited to 



