214 PHILOSOPHICAL TRANSACTIONS. [aNNO 1792. 



of the conversion of iron ? It is simply because its action on the metal seems, 

 in practice, pernicious ; I consider its presence as an evil, though a necessary 

 one, according to the present modes of working ; I was also anxious to try this 

 opinion by the test of experiment, and we see it has been fully confirmed. In 

 the last experiment, part of the iron was completely converted, and in some 

 others it seemed approaching fast towards nature, as the manufacturers express 

 it. It is indeed very possible to conceive a way in which air might be beneficial ; 

 that is, if it could be applied so as to burn the charcoal merely ; but at presents 

 for 1 grain of charcoal which it converts into carbonic acid air, it converts many 

 of iron into finery cinder ; and, as I have formerly shown, this is not the way 

 in which iron is actually converted in the reverberatory, and probably not in the 

 finery furnace. 



5. It is impossible to ascertain the principles of any art, without immediately 

 improving the practice, or opening a prospect of future improvement. The 

 preceding observations may serve to direct attempts to render the metallurgy of 

 iron less difficult, laborious, and expensive. For, 1. if a quantity of oxygene, 

 nearly sufficient to burn the charcoal, could be chemically combined with the 

 .cast iron, the operation would consume less fuel, and would not require so long 

 a time. It may be worth while to consider if the ores of iron, containing man- 

 ganese, owe any part of their value to this circumstance. 2. If it could be con- 

 trived to apply a sufficient heat to large quantities of iron in close vessels, and at 

 the same time to agitate them sufficiently, the loss in conversion would not per- 

 haps exceed 10 in 100. 3. The important object of converting hritish iron into 

 steel, may possibly be attained by following up reflections suggested by the fore- 

 going experiments. When the oxygene has been separated in the form of car- 

 bonic acid, there will remain the charcoal and iron, the constituent parts of 

 steel. Perhaps the materials, at a certain period of the process, may be so nearly 

 approaching to steel as to be easily convertible. The mass will contain also a 

 quantity of sulphur, on which perhaps the difficulty of making good steel from 

 our iron depends. But this difficulty, I am persuaded, will not be insuperable. 

 It may be proper to add, that whenever attention was paid to it, the hepatic 

 smell in the extricated air was perfectly distinguishable. 



I hope I may also be permitted to add, that whatever information or advantage 

 may be derived from these facts and observations, rnust be in a great measure 

 ascribed to the liberal curiosity of William Reynolds, whose enterprising spirit 

 and inventive genius have improved our machinery, enlarged our manufactures, 

 and changed the face of a large district in liis native county. 



P. s. The residuum of 486 grs. of cast iron, the same as that used in exper. 1, 

 weighed 48 J^ grs., after being dissolved in weak vitriolic acid, and heated to a 

 dull red heat ; the same quantity of iron, after the experiment, aiforded a resi- 



