586 Mr. J. Taylor's Lectures on Metallurgy. 



The metal of the greatest malleability is gold, which may 

 be beaten into leaves so thin, that they will float in the air like 

 a feather. Silver may be reduced to nearly the same state of 

 tenuity. Gold leaf is estimated at a thickness of little more 

 than the three-hundred-thousandth of an inch. Silver leaf is 

 about the hundred-and-sixty-thousandth. After these may be 

 ranked in the following order, copper, tin, lead, iron, and 

 zinc : this last, however, to be made perfectly malleable, must 

 be made somewhat hotter than boiling water. The other 

 malleable metals are platina, palladium, nickel, and mercury. 



It might at first sight appear that the ductility of metals 

 would follow the same order as their malleability, both pro- 

 perties being merely a mode of extension ; but it is evident 

 that the ductility of a substance is compounded of its mallea- 

 bility and tenacity. Hence iron, though by no means so mal- 

 leable as tin or lead, greatly surpasses them in ductility. 



The tenacity of metal is estimated by the weight that will be 

 required to break a wire of a given diameter. Thus it is stated 

 that a wire of 1-1 0th of an inch diameter of 

 Iron will bear 705lbs. before it breaks 



Copper ... 387 Silver 239 lbs. 



Platina ... 351 Gold 191 



The tenacity of tin is greatly inferior to that of gold, and the 

 tenacity of lead is the least of all, 



Metals, besides the properties described, have of course 

 others common to matter in general, or to bodies differently 

 constituted in other respects ; and some on which depend both 

 the uses we make of them, and the operations for making 

 them useful. 



The most important are those of divisibility and penetrabi- 

 lity, elasticity, affinity for each other, and affinity for other 

 substances. 



By the first affinity they unite together, forming mixed metals 

 called alloys or amalgams.. By the second they combine che- 

 mically with various substances which alter their character, 

 and form ores, salts, oxides, carbonates, hydrates, glasses or 

 enamels. 



From the properties of the metals, we are naturally led to 

 consider their uses, and the means by which they are converted 

 into the various forms that contribute so largely to the useful 

 and ornamental arts of life. 



In any state of society however rude, we can hardly con- 

 ceive of substances more desirable than the metals ; and thus 

 we see that among savage nations nothing is more coveted, 

 and that a few nails will be exchanged for their most highly 



prized 



