32 Philosophical Character of Dr. Priestley. 



ence. But, in other cases, his analogies were fanciful and unfound- 

 ed, and led him far astray from the path, which might have conduct- 

 ed him directly to truth. It is curious, however, as he himself ob- 

 serves, that in missing one thing, of which he was in search, he often 

 found another of greater value. In such cases, his vigilance seldom 

 failed to put him in full possession of the treasure upon which he had 

 stunibled. Finding by experience, how much chance had to do with 

 the success of his investigations, he resolved to multiply experiments, 

 with the view of increasing the numerical probabilites of discovery. 

 We find him confessing, on one occasion, that he " was led on, by 

 a random expectation of some change or other taking place." In 

 other instances, he was influenced by theoretical views of so flimsy 

 a texture, that they were dispersed by the first appeal to experiment. 

 " These mistakes," he observes, " it was in my power to have con- 

 cealed ; but I was determined to show how litde mystery there is in 

 the business of experimental philosophy ; and with how little saga- 

 city, discoveries, which some persons are pleased to consider great 

 and wonderful, have been made." Candid acknowledgments of this 

 kind were, however, turned against hrm by persons envious of his 

 growing fame ; and it was asserted that all his discoveries, when not 

 the fruits of plagiarism, were " lucky guesses," or owing " to mere 

 chance.* Such detractors, however, could not have been aware of 

 the great amount of credit, that is due to the philosopher, who at 

 once perceives the value of a casual observation, or of an unexpect- 

 ed result,; who discriminates what facts are trivial, and what are im- 

 portant; and selects the latter, to guide him through difficult and 

 perplexed mazes of investigation. In the words of D'Alembert, 

 " Ces hazards ne sont que pour ceux quijouent Men." 



The talents and qualifications, which are here represented as hav- 

 ing characterized the mind of Dr. Priestley, though not of the rarest 

 kind, or of the highest dignity, were yet such, as admirably adapt- 

 ed him for improving chemical science, at the time when he lived. 

 What Is then wanted, was a wider field of observation ; — an en- 

 larged sphere of chemical phenomena ; — an acquaintance with a far 

 greater number of individual bodies, than were then known; from 

 the properties of which, and from those of their combinations, tenta- 



* These charges, especially that of plagiarism, which had been unjustly advanced 

 by some friends of Dr. Higgins, were triumphantly repelled by Dr. Priestly, in a 

 pamphlet entitled, " Philosophical Empiricism," published in 1775. 



