215 



gatkm. What a barbarous and sordid life, we must 

 necessarily have lived, the Indians in the northern parts 

 of America, are a clear demonstration. 



And it is remarkable, that those which are of most 

 necessary use ? as iron and L-ad, are the most plentiful. 

 Those which may better be spared, are more rare. 

 And by this very circumstance they are qualified to be 

 made the common measure and standard of the value 

 of other commodities, 411 1 to serve for money, to which 

 use they have been employed by all civilized nations 

 in all ages. 



All metals are liable to rust. Gold itself rnsls, if 

 exposed to the fumes of sea-salt. The great instru- 

 ment in producing rust is water : air, only by the wa- 

 ter it contains. Hence in dry air metals do not rust; 

 neither if they are well oiled : water not being able 

 to penetrate oiL Rust is only the metal under ano- 

 ther form. Accordingly rust of copper may be turned 

 into copper again. Iron if not preserved from the 

 air by paint, will in time turn wholly into rust. 



7. Mines in general are cavities, within the earth, 

 containing substances of various kinds. These the 

 miners term loads : if metallic, they are said to be 

 alive; if not, to be dead bodies. In Cornwall and 

 Devonshire the loads always runs from cast to west. 

 Mines seem to be, or to have been channels of waters 

 within the earth, and have branches opening into them 

 in all directions. Most mines have streams running 

 through them ; where they have not, probably the 

 water has changed its coursed The springs in these 

 parts are always hard, abounding either with stony oc 

 sulphureo-saline particles. These particles are either 

 of a vitriolic or an arsenical nature. Thu first con- 

 cretes in to white cubes, resembling silver 3 thesecond into 

 yellow ones resembling gold. B.nh these are by the 

 termed mundic. 



8. Mundic is variously coloured, on the outside 

 with blue ; greenj purple, gold, sjlver 5 brass and copper 



