THE GREAT LONDON CHEMISTS 23 



seventeenth century. But the practice of interrogating 

 nature by experiment had sprung up, and was soon 

 destined to bear good fruit. Although these notions of 

 matter and its elementary forms lingered on until a much 

 later date, and indeed are not wholly extinct at the present 

 day, they received their first great blow about this time ; 

 the first brunt of an attack which was destined ultimately 

 to overthrow them. 



This attack was made by Boyle. The spirit in which 

 he approached the hostile ranks is best given in his own 

 words: 'For I am wont to judge of opinions, as of coins; 

 I consider much less in any one that I am to receive 

 whose inscription it bears, than what metal 'tis made of. 

 'Tis indifferent enough to me whether 'twas stamped 

 many years or ages since, or came but yesterday from 

 the mint. Nor do I regard how many or how few hands 

 it has passed through, provided I know by the touchstone 

 whether or no it be genuine, and does or does not deserve 

 to have been current. For if, upon due proof, it appears 

 to be good, its having been long and by many received 

 for such will not tempt me to refuse it ; but if I find it 

 counterfeit, neither the Prince's image nor superscription, 

 nor its date, nor the multitude of hands it has passed 

 through, will engage me to receive it. And one dis- 

 favouring trial, well made, will much more discredit it 

 with me, than all those spurious things I have named 

 can recommend it.' 



In this spirit the ' Sceptical Chymist, or considerations 

 upon the experiments usually produced in favour of 

 the four elements, and of the three chymical principles 

 of the mixed bodies' was written. In it, the various 

 theories of matter, which, like a river rising in the 

 remotest recesses of time had gathered tributaries as it 

 flowed and presented a formidable flood in Boyle's days, 

 were searchingly criticised. Every postulate was examined ; 



