CHAP. XL 



OF THE ATOMIC WEIGHTS OF ZINC, CADMIUM, 

 LEAD, TIN, BISMUTH, COPPER, MERCURY, AND 

 SILVER. 



THESE eight metals possess several properties in 

 common by which they are distinguished from 

 all the other metals. 1. They all possess a cer- characters 

 tain degree of malleability ; for bismuth, by far tais treated 

 the most brittle of them all, may be dimpled by chapter? 8 

 a blow of the hammer ; and zinc, the next in 

 order, is very malleable at a temperature some- 

 what above that of boiling water. 2. They all 

 melt at rather low temperatures, when compared 

 with the melting point of most of the other 

 metals ; for copper, which requires the greatest 

 heat to melt it, may be fused in a common fire 

 urged by bellows. It requires some care to keep 

 a silver crucible red hot in a common fire with- 

 out fusing it. The other six melt in a heat be- 

 low redness. Indeed, mercury requires so very 

 little heat to melt it, that it remains always fluid 

 even in our coldest winter weather. 3. Their 

 oxides are easily decomposed by heat and char- 

 coal, so that there is no difficulty in obtaining 



VOL, I. B b 



