214 Dr. Henry o« the Philosophical Character of Dr. Priestley. 



discoveries, upon the very confines of which they trod, but 

 which they left to confer glory on the names of less illustrious 

 followers. 



Of the general correctness of Dr. Priestley's experiments, 

 it is but justice to him to speak with decided approbation. In 

 some instances, it must be acknowledged that his results 

 have been rectified by subsequent inquirers, chiefly as respects 

 quantities and proportions. But of the immense number of 

 new facts originating with him, it is surprising how very few 

 are at variance with recent and correct observations. Even 

 in these few examples, his errors may be traced to causes con- 

 nected with the actual condition of science at the tiuie ; some- 

 times to the use of impure substances, or to the imperfection 

 of his instruments of research ; but never to carelessness of 

 inquiry or negligence of truth. Nor was he more remarkable 

 for the zeal with which he sougiit satisfactory evidence, than 

 for the fidelity 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 conceded to the great majority of 

 experimental philosophers, yet Dr. Priestley was singularly 

 exempt from that disposition to view phaenomena 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 attachment to hypotheses, and 

 to the facility with which he was accustomed to frame and 

 abandon them ; — a facility resulting not from habit only, but 

 from principle. " Hypotheses," he pronounces, 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 consider new facts only 

 as discoveries, and to draw conclusions for themselves." The 

 only exception to this general praise is to be found in the per- 

 tinacity 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 ph;enomena, which were considered by 

 almost all other philosophers as proofs of its utter unsound- 

 ness. But this anxiety, it must be remembered, was chiefly 

 apparent at a period of life when most men feel a reluctance 

 to change the principle of arrangement, by which tliey 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 higiiest j)hilosopliy, (and that there is such 

 a connection no one can doubt,) Dr. Priestley is entitled to 

 unqualified esteem and admiration. Attached to science liy 



the 



