LIB. II. 23. 201 



iriquisita migrat ad generationem, cum priiis non exis- 

 teret; aut contra migrat ad corruptionem, cum pritis 

 existeret. Itaque in utraque antistrophe, instantiate 

 tales sunt semper gemmae ; vel potius una instantia in 

 motu, sive transitu, producta ad periodum adversam. 

 At hujusmodi instautise non solum accelerant et robo- 

 rant ewclusivam, sed etiam compellunt affirmativam, 

 sive formam ipsam, in angustum. Necesse est enim ut 

 forma rei sit quippiam, quod per hujusmodi migratio- 

 nem indatur ; aut contra per hujusmodi migrationem 

 tollatur, et destruatur. Atque licet omnis exclusio pro- 

 moveat affirmativam, tamen hoc magis directe fit in 

 subjecto eodem, quam in diversis. Forma autem (ut 

 ex omnibus, qua? dicta sunt, manifesto liquet) prodens 

 se in uno, ducit ad omnia. Quo autem simplicior fu- 

 erit migratio, eo magis habenda est instantia in pretio. 

 Praeterea instantia migmntes magni sunt usus ad par- 

 tem operativam ; quia cum proponant formam copula- 

 tarn cum efficiente aut privante, perspicue designant 

 praxin in aliquibus ; unde facilis etiam est transitus ad 

 proxima 49 . Subest tamen in illis nonnihil periculi, 

 quod indiget cautione ; hoc videlicet, ne formam nimis 

 retrahant ad efficientem, et intellectum perfundant, vel 

 saltern perstringant, falsa opinione de forma, ex intuitu 

 efficientis. Efficiens vero semper ponitur nil aliud esse, 

 quam vehiculum, sive deferens forma?. Verum huic 

 rei, per exclusivam legitime factam, facile adhibetur 

 remedium. 



stone, which gradually lose them- is expressed in the well-known sen- 

 selves in the finer Marbles, till they tence, Nature non agit per sal- 

 can no longer be distinguished.&quot; turn. &quot; 



See Herschel s Discourse, 198, 199. 49 This is quite true. For &quot; Mi- 



&quot; The travelling Instances are cases grating Instances&quot; are simply regis- 



m which we are enabled to trace ters of phenomena arising from the 



that general law which seems to application (naturally or otherwise) 



pervade all Nature the law, as it of some agency to a substance, 



is termed, of Continuity, and which Chemistry is full of such cases. 



