METALS AND MINERALS. If 



to be drawn, out to the length of twenty-seven feet. 

 There are silver-mines in most parts of the world, 

 but those of Peru are by far the richest. The Abbe 

 "Kaynal says, that when the famous mines of Potosi 

 were first opened, a cwt. of ore yielded fifty pounds 

 of silver, but that at present the same quantity of ore 

 produces no more than two pounds of that metal. At 

 first the ore was found very near the surface of the 

 jnountain, but now the veins lie so low that the work- 

 men go down a descent of four or five hundred steps, 

 from which circumstances some suppose that these 

 celebrated mines are almost exhausted. 



Copper is a hard, heavy and ductile metal, abolincl- 

 ing with vitriol and an ill-digested sulphur called ver- 

 digrease, which renders utensils made of this metal, 

 unless kept very clean, extremely unwholesome. 

 Copper is found in many parts of Europe ; but the 

 mines of Sweden produce the greatest quantity. It 

 is dug up in large fragments of ore, which are first 

 beaten small, then washed to separate the earthy 

 parts, and afterwards smelted and cast into large 

 blocks. Bronze is a mixture of copper and tin. Two 

 parts of copper and one of zinc forms brass. 



Iron is a compound of different materials, and is 

 hard, fusible and ductile. In England there are many 

 iron-mines, but those of the forests of Dean, in Glou- 

 cestershire, are the most productive. If utility were 

 made the standard of estimation, iron would hold the 

 first place in the class of metals ; and would be ac- 

 peunted more valuable than gold, as it appears indis- 

 consably necessary to the carrying on of every art 

 and manufacture : at least it is certain that without the 

 use of iron it is impossible to bring any f them to per- 

 fection. This metal appears to be one of the principal 

 means of civilizing mankind. There hafc never been an 

 instance of a nation that understood the art of manu- 

 facturing iron but what in time attained to a degree 

 of civilization infinitely beyond that of the inhabi- 

 tants of those countries where this metal was Wanting, 

 or its use unknown. This, my dear sir, is n6t to be 

 wondered at, when you consider that if the iron-mine 



