HYPOTHESES OF BACON AND NEWTON. 163 



gases, vapours, and volatile liquids, there can no 

 longer be the shadow of a doubt that it is iden- 

 tical with the aBther of Newton, the pneumatical 

 power of Lord Bacon, and the universal igneous 

 principle of the ancient Greek philosophers. 

 Nor is it possible to doubt that Newton regarded 

 this principle as the proximate cause of cohesion, 

 capillary attraction, chemical affinity, and of 

 universal gravitation ; all of which he viewed as 

 modified effects of one and the same agent.* 

 It was owing to the vague and imperfect account 

 which he gave of its modus operand^ that philo- 

 sophers have even doubted the reality of its ex- 

 istence, and treated it as a chimera of the author's 

 imagination, invented for the purpose of sus- 

 taining his theory of nature ; the consequence 

 of which has been, that the law of gravitation 

 has been regarded as a comprehensive gene- 

 ralization of aggregate movements, for which no 

 definite reason can be assigned : while the great 

 and noble science of chemistry, which, in a 

 practical point of view, is far more important 

 than astronomy, consists of an immense collection 

 of facts and experiments, the connection of which 

 with the phenomena of heat, light, electricity, 



* It is now universally admitted, that the force with which 

 menstmums dissolve, and combine with solid bodies, is an 

 exertion of chemical attraction ; a force which Newton referred 

 to the aether, as I before stated, page 26 ; and I shall demon- 

 strate hereafter, that caloric is not only the universal solvent of 

 nature, but that it is the only agent by which liquids are enabled 

 to combine chemically with solids. 



