CHAP. II. 



OF THE ATOMIC THEORY. 



Two opinions have divided philosophers respect- Opinions 

 ing the nature of the ultimate elements of bodies, the ultimate 

 ever since they began to speculate on the subject. s 

 According to one party, these ultimate elements 

 consist of atoms, or particles, incapable of farther 

 division ; according to another, matter is infinite- 

 ly divisible, and consequently no such atoms can 

 exist. These two opinions divided the ancients ; 

 and, after the revival of science in modern Eu- 

 rope, we find them equally dividing the philoso- 

 phical world, and splitting it into sects. About 

 the beginning of the last century, the infinite di- 

 visibility of matter was a favourite subject of dis- 

 cussion in Great Britain, and seems to have been 

 universally adopted. Dr. Keil, in his Introduc- 

 tion to Natural Philosophy, devotes three lectures 

 to this subject. In the first, he demonstrates the 

 infinite divisibility of matter ; in the second, he 

 answers the objections which have been advanced 

 against the truth of the doctrine ; and in the 

 third, he gives a number of examples of the ex- 

 treme subtilty of matter, by showing how very 

 minute a portion of certain substances may be 

 made visible to the eye, or distinguished by the 



