EFFECTS OF POTASSIUM ON IRON. 53 



A small bar four lines th'ck was bent backward and for- and cold, 

 ward cold, but it broke after repeated ben<ji t^ The outer Broke. 

 surface of the iron was a dull platina white. The fracture 

 e^xhibited a white vim, tine grained, and stronj^ly compressed, 

 from 8 to 15 tenths of a line broad; and this vim tmciosed a 

 brown nucleus from 2 lines to 2'75 broad. The aucleus, 

 completely separate from the rim, and having but a slight 

 adhesion to it, was composed of white and brown grains 

 weakly united. It was formed of the interior surface of the 

 barrel, which had been most exposed to she action of the 

 potash. The outer iron was soft, and easily filed and Hat- 

 ted cold. 



Another bar forged thin was tempered, after being heated Tempered. 

 to a cherry red. Is surface was hard when filed, and the 

 metal retained its malleability. It did not break, till it had 

 been bent several times. Its fracture appeased similar to 

 that of the iron which had not been tempered. 



From ai! these trials we may conclude, that the iron ap- The iron com- 

 pears to have combined with the potash in the guubanel in t>ined with 



, . . . . , . , . . potassium in 



two ditierent proportions; one a minimum, which gives iron two propor- 



a, white colour resembling that of platina; the other a raaxi- tions: 

 mum, which gives it a brown colour mingled with white specks: 



That the iron potassated at a maximum is easily wrought a small pro. 



hot or cold, that it becomes more malleable by this combi- P°'"°" '»"- 



11- -11 proved, 



nation, and that it can acquire hardness by tempering with- 

 out becoming brittle like steel; consequently it is highly 

 probable, that the small quantity of potassium, which com- 

 bines with iron when it is smelted with charcoal, can only 

 contribute to improve its quality: 



That iron potassated at a maximum acquires a brown hue a large injur- 

 more or less deep, mingled with larger or smaller white®''*'" 

 specks ; and that in this state the particleshave less cohesion, 

 so that jthe iron becomes coldshort, and very probably redi-hort. 



A single experiment on the combination of potash with but one trial, 

 iron may give some idea of tiie new properties the metal "o' sufficient 

 acquires during and after it is wrought; but it would be too 

 hasty to conclude absolutely respecting the qualities of potas- 

 sated iron from a single trial. VVe must wait therefore till 

 farther experiments shall confirm the whole of the results 

 we obtained, refute some of them, or add new ones, whea 

 we may decide with more certainty. 



VII. 



