CHAPTER XVIII 



THE CLASSIFICATION OF THE ELEMENTS 



A. METALS AND NON-METALS 



A " sceptical chemist's " views on the elements (Boyle 



1661). Until the close of the alchemistic period, it was 

 universally agreed that all matter was composed of a very 

 small number of " principles " or " elements," e.g. the four 

 elements, earth, air, fire and water of Aristotle and the 

 Peripatetic School, or the three principles, mercury, sulphur 

 and salt, of Albertus Magnus (1205-1280) and the alchem- 

 ists. The modern conception of elements is due to Boyle, 

 who sets out his views in the first pages of " The Sceptical 

 Chymist " * as follows : 



" I perceive that divers of my Friends have thought it 

 very strange to hear me speak so irresolvedly, as I have 

 been wont to do, concerning those things which some take 

 to be the Elements, and others to be the Principles of all 

 mixt Bodies. But I blush not to acknowledge that I much 

 less scruple to confess that I doubt, when I do so, than to 

 profess that I know what I do not " (Sceptical Chymist, 

 1661, 1-2). 



In discussing " the number of Elements or Principles " it 

 was agreed to use "elements and principles as terms equi- 

 valent : and to understand, both by the one and the other, 

 those primitive and simple bodies of which the mixed ones 



1 The Sceptical Chymist: or Chymico-physical Doubts and Paradoxes 

 touching the Experiments whereby vulgar Spagyrists are wont to 

 endeavour to evince their Salt, Sulphur and Merctiry, to be the True 

 Principles of Things. London, 1661. Compare Works,l72.$,\\\. 261. 



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