CHEMICAL SCIENCE. 



215 



These results show that these metals exert no actioiron each other, as the 

 numbers indicating the degrees of hardness of their alloys are rather less 

 than those required by theory. Our researches on the conductibility of heat 

 by the three above series of alloys, throw, we believe, some light on the great 

 difference which the alloys of bronze present, as compared with those of tin 

 and zinc ; for we have stated above, that the latter conduct heat as a mix- 

 ture of metals would do, and not as the former series, which conduct heat as 

 definite chemical compounds. 



We shall conclude by giving the degree of hardness of two other series of 

 alloys, viz., those composed of lead and antimony, and lead and tin. In the 

 series of lead and tin, we find that tin also increases the hardness of lead, 

 but not in the same degree as it does that of copper. 



Lead and Antimony 



ON THE CHEMICAL CHANGES WHICH PIG IRON UNDERGOES DURING 

 ITS CONVERSION INTO WROUGHT IRON. 



The following important communication has been made by Mo^rs. Cal- 

 vert and Johnson, of England, to the L. E. and D. Philosophical Magazine : 



