c/ Experimental Philqfophy. ^^ t 



inflammable, like gall-ftones. Dr. Heberden has,:, 

 alfo, favoured me with fimilar information, re- 

 fpeding their analyfis. On the other hand, I 

 have fully fhewn, that thefe fubftances vary in 

 their (trudure and compofition ; that calcination 

 converts fome into quicklime; that others are 

 CDnfumed entirely in the fire-, and that a third 

 Ibrt yield, after burning, an infipid refiduum, 

 incapable of giving any impregnation to water. * 

 What then are we to infer from premifes, appa- 

 rently fo inconfiftent ? Let us deduce from them 

 thefe falutary leflons ; that dogmatifm is unbecom- 

 ing a philofopher; that fallacy may attend our 

 cleared views; and that unperceived diverfities, 

 in the fubjeds of our inveftigation, may render 

 truth compatible with contrariety of evidence. 



An eagernefs to eftablifh fyftems, and a fafti- 

 dious difdain of perplexity, contradiclion, or dif- 

 appointment, are difpofitions highly unfavourable 

 to phyfical inveftigation. Lord Bacon has well 

 obferved, " that one, who begins with certain- 

 " ties, fhall end in doubts; but if he will be 

 ** content to begin v/ith doubts, he (hall end in 

 ** certainties." f The progrefs of Icience is ufu- 

 ally flow and gradual ; and in all ordinary cafes, 

 the race is not to the fwift, but to the fteady, the 

 patient, and the perfevering. A man of lively 



* Philofoph. Medic, and Experim. Effays, vol. Ill, p. l6i. 

 t Advancement of Learning. Book I. p. 20. 



parts. 



