IRON. 189 



LESSON XLIIL 



IRON, COPPER, TIN, AND LEAD. 



OF all the mineral bodies which God has pro- 

 vided for our use, iron is the most universally 

 valuable. The purposes to which it is applied are 

 almost numberless. By its means man chiefly 

 supplies his wants, as without it agriculture could 

 never have arrived at any perfection, nor the 

 plough have rendered the earth fertile. It is also 

 essential in the preparation of other metals, mi- 

 ning-tools of all sorts being made from it, so 

 that were it not for iron, the mineral stores of the 

 world would not have been available to us. 



The greatest part of our manufacturing ma- 

 chinery is constructed of iron ; and it is largely 

 used at the present time in building houses, mills, 

 and bridges, and in making rail-roads and steam- 

 engines : stoves, cannon, knives, scissors, saws, 

 scythes, and cutlery of every kind are likewise 

 made from it. 



Steel is iron, which has been made red-hot in a 

 charcoal fire. This may be hardened to any de- 

 gree by being heated, and then suddenly cooled 

 by plunging it into cold spring water. The tem- 

 per given to steel by this mode of proceeding is 

 so great, that a sword properly prepared will cut 

 through iron without its edge being turned, or it 

 will divide a hair or a down feather. 



Iron-ore is found in many parts of the world, 



