On the ' Mature of Heat. 321 



has been fuppofcd by fome, could not have effefted the phae- 

 noinena defcribed : for no fiich change could be difcovered 

 to have taken place ; and if it hrd, it ought to have been fuf- 

 ficiently great to have accounted for alJ the heat that was 

 produced. In reflefting on this experiment, we cannot but 

 admit, that with the preient means of" our knowledge we are 

 incapable of" explaining the efi"ecl: that is produced; yet it 

 would not be very philofophical to conclude, that any iylkm 

 was abfolulely falfe, which, though it readily folved tlie chief 

 .pha'noniena required, might, in lome infolaled infhnce, be 

 found apparently incompetent to tlie talk*. Should we not, 

 if our f"y(tem be previouily founded on a broad and iolid in- 

 duction, and cftablifhed on the firm bafis of experiment, be 

 led to attribute rather any deficiency of explanatiijn in any 

 particular inflance, to a want of knowledge of fome minute 

 hnks in the chain, than as involving any infuperable ohftacle 

 to the dodlrine itfelf ? And fliould'it not lead us, inftead of 

 abandoning, to review our theory with more circumfpcctioa 

 and a grc;ater caution ? 



_ No one will be- inclined, perhaps, to difputc the Newto- 

 nian theory of gravitation, yet there are jihsnomena which 

 It is difficult to conceive how it accounts for. Thus it would 

 fceni aconlradiclion to the edabliihed principles of our great 

 phiJofoplier, to fuppofe that a body divided into parts, how- 

 ever ininute, can poflibly afcend in a fluid fpecifically lighter 

 than itfelf. A little acquaintance with the operations (if che- 

 miftry will fliow that this is a hA that occurs in the folution 

 of various iolids, and that without any motion being com- 

 nuinicated to the velfei containing them; the folid becoming 

 diifufed throughout the fubftancc^of the dili'olving fluid, and 

 :ippcaring to overcome the natural tendency of bodies towards 

 the centre of the earth, and to have fome new power of alccnt 

 jniprcfi"ed on iis particles. 



To conclude, then, it appears that we are entitled to con- 

 fider caloric, in ihc prefent Uate of our knowledge, as a fub- 

 i'iaiicc fui gau-rix, not becaufe we can fenfibly den)on(lrate 

 the truth of our opinion, but becaufe it is the lead excep- 

 tionable theory of the two, and becaufe the ph.'cnomenon of 

 iieat admits from it an interpretation more finiple and ob- 

 vious, and more agreeable to the analogy of nature. P. 



' If our C()rrcf|-o:idcnt had attcndcii toiliis f;i£l, tlwt in tlic cxperiincurs 

 alluded t(i, tlic Cminr, with all the care nnd [ireiiiution lie cinpJoyrH, li; d 

 not fucci-tiltd in iuluiatiii;'. t'rom tht co'iiai'.t of cdoric the bodic* Jubjccitd 

 to fndiDii, iiu wovUi pot hsive; (nund.thom fia.id at aij in the wjty of his 

 hrt^umciit. Was not the aj^prtratUi wholiy imtntricd in a bath of caloric — 

 til- afiiKiljihirt : — ILdiT. ' ' -.- . 



Vor. \il. No. 48. X I.V. Or. 



