DIVISIBILITY. 19 



example, a gold leaf may be hammered till 55^ of an 

 inch in tliiclmess, or one thousand times thinner than 

 a leaf of this hook. A silver wire may he coated with 

 gold, and then drawn out so fine that the gold coating 

 shaU become a thousand times less than the gold leaf 

 itself. So attenuated is one of the threads of a small 

 spider's web, that half a pound would reach round the 

 globe. It has been found that tripoh, a mineral used 

 .in the arts, is made up of shells of exceedingly minute 

 animals, so small that a single cubic inch contains forty 

 thousand millions, or fifty times as many individuals 

 as there are human beings on the face of the earth. 

 Hundreds of animalcules (or minute animals) have 

 been seen with a microscope in a single drop of water, 

 without in the least degree affecting its transparency. 

 Some of these are so small that thousands could rest, 

 without crovv^ding, on the point of a pin ; yet these 

 have blood-vessels, muscles, and other parts, as well as 

 larger animals. Still more minute appears to be the di- 

 vision of those substances which are constantly throw- 

 ing oft' odors or perfumes. A grain of musk wiU scent 

 the air of a room for years, with particles inconceivably 

 minute ; and a bed of flowers will fill the air with their 

 odor, as hundreds of miles of the breeze successively 

 pass over them, with an insensibly small portion of 

 their own weight. 



But no division, however minute, ever destroys mat- 

 ter ; every particle still retains its identity ; and the 

 largQgt mountains, weighing millions of tons, are made 

 up of these innumerable particles. 



