Messrs. F. C. Calvert and R. Johnson on Alloys. 243 



Iron 74'GO 



Potassium . . . 25*40 



100-00 



which leads to the following formula : — 



4 equivalents of iron . . . 112 = 74-17 

 1 equivalent of potassium . . 39 = 25-83 



T51 = 10000 

 Therefore, instead of obtaining an alloy having the definite 

 proportions we had employed, we obtained one containing much 

 more iron. This alloy had all the appearance of malleable iron, 

 and could be forged and welded; but what was very extraordinary, 

 and which much surprised us, was its extreme hardness, so much 

 so that at natural temperatures it was hardly dented when ham- 

 mered with a heavy sledge hammer, and was barely affected by the 

 file; and what was not less interesting, was, that although this 

 alloy contained upwards of 25 per cent, of potassium, or one of the 

 most powerful electro-positive substances, still the iron of the 

 alloy oxidized rapidly in the atmosphere and under water. It is 

 certainly to be much regretted that such is the result ; for if, by 

 alloying with a metal more electro-positive than itself, we had 

 succeeded in obtaining an alloy of iron not oxidizable, we should 

 have discovered a most valuable fact for manufactures, and one 

 which has occupied so deeply the thoughts of all those connected 

 with such improvements. 



We made another experiment with the same proportions of 

 bitartrate of potash and iron, only we added some charcoal 

 finely pulverized, and obtained the following result : — 



Iron 81-42 



Potassium . . . 18-58 



100-00 

 which leads to the formula : — 



6 equivalents of iron . . . 168 or 81* 16 

 1 equivalent of potassium . . 39 ... 18-84 



207 ...10000 

 We are led to think that this alloy contained an excess of iron, 

 for there v;as on its surface a thin layer of cast iron ; and although 

 we filed it off as carefully as possible, still no doubt some of it 

 had introduced itself into the mass. As this alloy presented all 

 the pro])erties of the former, we shall not enter into details re- 

 specting it. With the view of obtaining this alloy, if possible, 

 by a cheaper process, we submitted for several hours to an intense 

 heat a mixture of fine iron fihngs with a quantity of carbonate 



