18 LETTER V. 



as to form the terraqueous globe, the surface of which 

 is diversified with so enchanting a scenery and 

 through infinite goodness rendered productive of 

 every thing necessary for the comfortable support 

 of human and animal existence, without casting a 

 glance on the conveniences and riches contained 

 within its bowels. I shall not take up your time 

 in tasking you to pore over a volume of mineralogy, 

 I shall only exhibit to your view some of the most 

 remarkable characteristics and qualities of those me- 

 tals, minerals, and other subterraneous productions of 

 the earth which are of the greatest utility to man or 

 have obtained the highest place in his estimation. 

 Of metals, the principal are gold, silver, copper, iron, 

 lead and tin, and according to the enumerations made 

 by some mineralogists we may add mcrcuy, or quick- 

 silver. 



Gold is the heaviest, purest and most docile of all 

 metals. It is found in mines and sometimes in small 

 grains in the sandy bottoms of rivers, which last is 

 called gold dust. There are gold mines in many- 

 parts of the world, but few have been discovered iu 

 Europe, and those so unproductive as not to be 

 worth the expence of working. The mines of Mexi- 

 co and some other countries of Spanish America are 

 the richest ; but very fine gold is also found in some 

 parts of Africa and the East Indies. Of all the pro- 

 perties of this metal its ductility is the most surpri- 

 sing. A single ounce of gold may be extended to a 

 surface of an hundred and fifty square feet, and yet 

 it will remain so entire that not the least flaw can be 

 perceived even by the help of the best jnicroscope. 

 Mr. Boyle says, that gold may be drawn into so fine 

 a wire, that an ounce will extend an hundred and 

 fifty-live miles and an half, or even to a much greater 

 distance. In gold mines there is often found another 

 metal called platina, which is the heaviest of all sub- 

 stances, and much harder than gold or silver. 



Next to gold, silver is the most valuable of all me- 

 tals as as well as the finest and most ductile. Mr. 

 Boyle says that he procured a single grain of silver 



