260 NOVUM ORGANUM. 



*^ qui movetur localiter et expansive manifesto neque tamen col- 

 ligit manifestum augmentum caloris, rejice etiam motum loca- 

 lem aut expansivum secundum totum. 



12. Per facilem tepefactionem omnium corporum, absque 

 aliqua destructione aut alteratione notabili, rejice naturam de- 

 structivam aut inditionem violentam alicujus naturae novae. 



13. Per consensum et conformitatem operum similium quae 

 eduntur a calore et a frigore, rejice motum tarn expansivum 

 quam contractivum secundum totum. 



14. Per accensionem caloris ex attritione corporum, rejice 

 naturam principialem. Naturam principialem vocamus earn 

 quae positiva reperitur in natura, nee causatur a natura praece- 

 dente. 1 



Sunt et aliae naturae: neque enim Tabulas conficimus per- 

 fectas, sed exempla tantum. 



Omnes et singulae naturae praedictae non sunt ex Forma 

 Calidi. Atque ab omnibus naturis praedictis liberatur homo in 

 operatione super Calidum. 



XIX. 



Atque in Exclusiva jacta sunt fundamenta Inductionis verae ; 

 quae tamen non perficitur donee sistatur in Affirmativa. Neque 

 ^ vero ipsa Exclusiva ullo modo perfecta est, neque adeo esse 

 potest sub^initiis. Est enim Exclusiva (ut plane liquet) rejectio 

 naturarum simplicium ; quod si non habeamus adhuc bonas et 

 veras notiones naturarum simplicium, quomodo rectificari potest 

 Exclusiva? At nonnullae ex supradictis (veluti notio naturae 

 elementarisj notio naturae coelestis, notio tenuitatis) sunt no- 

 tiones vagae, nee bene terminatae. Itaque nos, qui nee ignari 

 sumus nee obliti quantum opus aggrediamur (viz. ut faciamus 



1 Bacon here anticipates not merely the essential character of the most recent 

 theory of heat, but also the kind of evidence by which it has been established. The 

 proof that caloric does not exist, in other words that heat is not the manifestation 

 of a peculiar substance diffused through nature, rests mainly on experiments of 

 friction. 



Mr. Joule and Professor Thomson ascribe the discovery of this proof chiefly to 

 Sir Humphrey Davy (see Beddoes's Contributions to Physical and Medical Knowledge, 

 p. 14.) : but though Davy's experiments guard against sources of error of which Bacon 

 takes no notice, the merit of having perceived the true significance of the production 

 of heat by friction belongs of right to Bacon. 



It is curious that in the essay in which he opposes the doctrine of caloric, Davy 

 endeavours to introduce a new error of the same kind, and to show that light really 

 is a natura principialis, a peculiar substance which in combination with oxygen pro- 

 perly so called constitutes oxygen gas, which he accordingly calls phosoxygen. 



