the Philosophical Character ofDr Priestley. 9 



he sought satisfactory evidence, than for the fideUty with which 

 he reported it. In no one instance is he chargeable with mis- 

 stating, or even with straining or colouring, a fact, to suit an 

 hypothesis. And though this praise may, doubtless, be con- 

 ceded to the great majority of experimental philosophers, yet 

 Dr Priestley was singularly exempt from that disposition to 

 view phenomena through a coloured medium, which sometimes 

 steals imperceptibly over minds of the greatest general probity. 

 This security he owed to his freedom from all undue attach- 

 ment to hypotheses, and to the facility with which he was accus- 

 tomed to frame and abandon them ; — a facility resulting not 

 from habit only, but from principle. " Hypotheses" he pro- 

 nounces, in one place, " to be a cheap commodity ;*" in another 

 to be *' of no value except as the parents of facts ;" and so far 

 as he was himself concerned, he exhorts his readers " to consi- 

 der new facts only as discoveries, and to draw conclusions for 

 themselves."' The only exception to this general praise is to be 

 found in the pertinacy with which he adhered, to the last, to 

 the Stahlian hypothesis of phlogiston ; and in the anxiety which 

 he evinced to reconcile to it new phenomena, which were con- 

 sidered by almost all other philosophers as proofs of its utter 

 unsoundness. But this anxiety, it must be remembered, was 

 chiefly apparent at a period of life, when most men feel a reluc- 

 tance to change the principle of arrangement, by which they 

 have been long accustomed to class the multifarious particulars 

 of their knowledge. 



In all those feelings and habits that connect the purest morals 

 with the highest philosophy (and that there is such a connec- 

 tion no one can doubt), Dr Priestley is entitled to unqualified 

 esteem and admiration. Attached to science by the most gene- 

 rous motives, he pursued it with an entire disregard to his own 

 peculiar interest. He neither sought, nor accepted when offer- 

 ed, any pecuniary aid in his philosophical pursuits, that did not 

 leave him in possession of the most complete independence of 

 thought and of action. Free from all little jealousies of con- 

 temporaries or rivals, he earnestly invited other labourers into 

 the field which he was cultivating ; gave publicity, in his own 

 volumes, to their experiments ; and with true candour, was as 

 ready to record the evidence which contradicted, as that which 



