4 FERGUSON'S LECTURES. 



over, it would be absurd to say that the greatest moun- 

 , tain on earth has more halves, quarters, or tenth parts, 

 than the smallest particle of matter has. 



We have many surprising instances of the smallness 

 to which matter can be divided by art : of which the two 

 following are very remarkable. 



1. If a pound of silver be melted with a single grain of 

 gold, the gold will be equally diffused through the whole 

 silver ; so that, taking one grain from any part of the 

 mass (in which there can be no more than the 5760th 

 part of a grain of gold) and dissolving it in aquafortis, 

 the gold will fall to the bottom. 



2. The goldbeaters can extend a grain of gold into a 

 leaf containing fifty square inches ; and this leaf may be 

 divided into 500000 visible parts. For an inch in length 

 can be divided into 100 parts, every one of which will 

 be visible to the bare eye : consequently a square inch 

 can be divided into 10000 and 50 square inches into 

 500000. And if one of these parts be viewed with a 

 microscope that magnifies the diameter of an object only 

 10 times, it will magnify the area 100 times ; and then 

 the 100th part of a 500000th part of a grain (that is, the 

 50 millionth part) will be visible. Such leaves are com- 

 monly used in gilding ; and they are so very thin, that if 

 124500 of them were laid upon one another, and pressed 

 together, they would not exceed one inch in thickness. 



Yet all this is nothing in comparison of the lengths 

 that nature goes in the division of matter. For Mr. 

 Leewenhoek tells, us that there are more animals in the 

 milt of a single cod-fish, than there are men upon the 

 whole earth : and that, by comparing these animals in a 

 microscope with grains of common sand, it appeared 

 that one single grain is bigger than four millions of them. 

 Now each animal must have a heart, arteries, veins, 

 muscles, and nerves, otherwise it could neither live 

 nor move. How inconceivably small then must the par- 



