468 D'ALEMBERT. 



incapacitated from such pursuits by his entire ignorance 

 of many branches of physical science, an ignorance almost 

 general with him on every thing which did not lend itself 

 to geometry or rather analysis, an ignorance, be it 

 further observed, extremely discreditable to his under- 

 standing as a philosopher. Who can read without 

 astonishment his avowal that he knows nothing of che- 

 mistry ; an avowal borne out by some of his writings, and 

 by the Discourse to the ' Encyclopedic;' when we reflect 

 at the same time, that the greatest of geometricians and 

 analysists did not disdain to be as thoroughly acquainted 

 with the chemistry of his age, as any one who knew 

 nothing else ? Indeed some of his most wonderful con- 

 jectures respecting the constituent parts of bodies, may be 

 referred as much to chemical as to optical science.* 



D'Alembert's reason for undervaluing the truths of in- 

 ductive philosophy, must be allowed to have been wholly 

 unworthy of his genius for general speculation. He 

 thought meanly of the evidence on which it rests, and 

 could take no interest in any investigations other than 

 analytical. Can any one doubt that the evidence of 

 experiments is in the highest degree deserving of our 

 respectful attention, without refusing also his approval to 

 the whole of human conduct, which of necessity proceeds 

 upon the admission that contingent truths, both physical 

 and moral, rest on sufficient grounds for us safely to act 

 upon them in all the affairs of life? Besides, D'Alernbert 

 admitted, both in theory and by his own conduct, that 

 physical science was deserving of attention, when it could 



* See especially the Queries to the ' Optics.' I remember Dr. Black 

 citing these wonderful productions with unbounded admiration. 



