On iie Carkn which exijis in Iron and Steel. 211 

 the furface of the fluids. This circumftance confirmed 

 what had long heen evident to me, from a knowledge of the 

 principles and the mode of conveying them in manufacturing 

 both thefe ftates of iron, that the carbon in crude iron and 

 that infteel exifledin a widely different mode of union. And as 

 in the latter it exifted not in a crude ftate, I was led to con- 

 clude that an aeriform chemical union was effected, during 

 the procefs of cementing the fteel, by the agency of the 

 caloric on the charcoal, which ftratifies the bars during the 

 operation. 



In my correfpondence, however, with the Editor of the 

 Philofophical Magazine, he threw out fome hints that a 

 different kind of chemical union might be effefted by the 

 fame agency, and that in fteel the carbon might exift in 

 a concrete ftate, though not crude- neutral, though not 

 aeriform. This combination, which I had overlooked, 

 (humanum eft errare!) appeared fo highly probable that I re- 

 fumed my experiments ; . and I am happy in now ftating 

 that this idea was juft, as I have fince obtained from fteel 

 carbon in the ftate of an impalpable powder, by the follow- 

 ing fimple operation. 



I introduced into a glafs veflel a plate of polifhed fteel, 

 and poured upon it as much clear rain water as covered it 

 three inches. In this ftate it remained for 50 days, during 

 which time I carefully obferved the agency of the water 

 upon the metal. Twenty-four hours after introduction, 

 minute flakes were obferved floating lightly in the water; 

 they increafed on the fecond and third days, and fell gradu- 

 ally towards the bottom. As thefe accumulated, the furface 

 of the water became covered with the fame carbonaceous 

 pellicle mentioned above *, exactly refembling the coloured 

 film which is frequently found floating upon the furface of 

 fprings where iron is precipitated from the carbonic acid. 



• A plate of pure malleable iron underwent a fimilar immerfion in a 

 feparate veflel, but exhibited no difengagement of carbon in this ftate. 



P % During 



