74 MEMOIR OF DR. DALTON, AND 



CHAPTER IV. 



HISTORY OF THE ATOMIC THEORY. 



IDEAS OF MATTER UP TO THE TIME OF LUCRETIUS. 



There is no chapter in the history of man more marvellous 

 than that which deals with his conception of matter. 

 There has been the greatest difficulty in all ages in com- 

 prehending its existence, and still more so in conceiving 

 how it can be constituted of so many different substances. It 

 seems, beyond expression, strange, that although himself 

 made of matter, and exposed so frequently to the pain 

 of living in regions covered with most inhospitable forms 

 of it, or tossed about in an unmanageable ocean of the 

 same, he should still for a long lime confuse the conception 

 of it with spiritual existence, and still longer fail to obtain 

 any distinct idea of the cause of their diversity. I do not 

 allude only to the metaphysical difficulties even now unsolved 

 as to the existence of matter, but to those perhaps most 

 apparent in the history of the physical sciences. The diffi- 

 culties have begun with the savage who scarcely distinguishes 

 the wood from his divinity, and still less divides substances 

 into classes. They are difficulties which, in one form or 

 other, have struggled long in man, and the progress of which 

 may be seen perhaps most clearly in the Greek, but more or 

 less in all nations who have thought on philosophical subjects, 

 whilst the struggle in Europe in the middle ages was long 

 and violent, occupying the most active minds of the age. It 

 is strange to observe the pertinacity of man in deciding that 

 matter is one, that all substances have the same substratum 



