122 MEMOIR OF DR. DALTON, AND 



The doctrine of elementary atoms, either in the sense of 

 indivisible or merely undivided, leads us to suppose all things 

 formed of one substance only ; and this seems to have been 

 the notion of those who have held it up as a solution of the 

 question, although generally it has not been carried out far 

 enough to arrive at the difficulties. If all the elementary 

 bodies are the same as this notion supposes, every change is 

 made by change of position of the particles. This is the 

 early doctrine again. 



In speaking of the atoms, Boyle says, " little particles of 

 various sizes and shapes variously moved." This "variously 

 moved" introduces a force; it is the introduction of various 

 powers and qualities, and, consequently, of what we term 

 elements. This shews the difficulty of obtaining correct 

 language, when Boyle, whose object was to be accurate, 

 seemed to have overlooked this in those few but important 

 words. 



I may quote the graphic words of Boyle, shewing what 

 confused ideas reigned on the nature of combination. " Hel- 

 mont we know, too, asserts that all mixed bodies spring from 

 one element; and that vegetables, animals, marcasites, stones, 

 metals, &c., are materially but simple water, disguized into 

 these various forms by the plastic virtue of their seeds."* 

 ** Aristotle tells us, that if a drop of wine be put into ten 

 thousand measures of water, the wine being overpowered by 

 so vast a quantity of water, will be turned into it. But if 

 this doctrine were true, one might hope, by melting a mass 

 of gold and silver, and by but casting into it lead and anti- 

 mony, grain after grain, we might, at pleasure, within a 

 reasonable compass of time, turn what quantity we desired 

 of the ignoble into the noble metals." f 



Lemery, born about twenty years after Boyle, felt, but 

 not very clearly I imagine, some of these difficulties, as he 



♦ Sceptical Chymist. Vol. III., p. 284. f Page 289. 



