LIBER QU1NTUS. 629 



attamen haec Sagacitas per Expcrientiam Literatam plurima 

 interim ex iis quae in proximo sunt in genus humanum (tan- 

 quam missilia apud antiques donativa 1 ) projiciet et sparget. 

 Superest ilia Translatio de Parte Artis in Partem diversam ; 

 quae parum differt a translatione de arte in artem. Verum 

 quia artes nonnullae spatia magna occupant, ut etiam Transla- 

 tionem Experimentorum ferre intra seipsas possint, hanc etiam 

 speciem Translationis subjungere visum est. Praecipue, quia 

 magni prorsus est in nonnulla arte momenti. Plurimum enim 

 ad artem Medicinae amplificandam profuerit, si. experimenta 

 partis illius medicinae de Curationibus Morborum ad partes 

 illas de Tuenda Sanitate et Prolongatione Vitae transfer ant ur. 

 Si enim opiatum aliquod insigne ad spirituum in morbo pestilenti 

 furibundam incensionem reprimendam suffecerit, non dubitet 

 quispiam, quin simile aliquod, debita dosi familiare redditum, 

 etiam incensionem earn gliscentem et obrepentem quae per 

 aetatem fit aliqua ex parte fraenare et retardare possit. Atque 

 de Translatione Experiment! hactenus. 



Inversio Experiment! fit, cum contrarium ejus quod Experi- 

 mento constat probatur. Exempli gratia ; Calidum per Specula 

 intenditur : num etiam Frigidum ? 2 Item, Calidum se diffun- 

 dendo fertur tamen potius in sursum : num etiam Frigidum se 

 diffundendo fertur magis in deorsum ? Exempli gratia ; acci- 

 pias bacillum ferreum, illudque in uno fine calefacias ; et deinde 

 erigas ferrum, parte calefacta subtus locata, in superiore parte 

 manu apposita ; actutum manum aduret ; parte autem calefacta 

 supra locata, et manu subtus, multo tardius aduret 3 : num etiam, 

 si totum bacillum calefiat, et finis alter nive vel spongia in aqua 

 frigida tincta madefiat ; si nix aut spongia superius locetur, num 

 (inquam) frigus deorsum mittet citius, quam inferius locata 

 sursum ? Item, Radii Solis supra album dissiliunt, supra nigrum 



1 See for an illustration of this phrase Sueton. in Calig. c. 18. 



2 With Bacon, as with the Peripaticians, cold is not the negation of heat ; it is 

 something positive the opposite of heat, and not merely its absence. Prevost's ex- 

 periment, in which two concave mirrors are placed opposite to one another with a 

 piece of ice in the focus of the one and a thermometer in that, of the other, shows that 

 the effect apparently due to the radiation of cold may be made more intense in the 

 manner which Bacon suggests : the real explanation of the phenomenon of course de- 

 pends upon the " theory of exchanges." 



8 It is obvious that the difference arises simply from the circumstance that the 

 air close to the hot end of the rod rises in the one case to that at which the hand is 

 applied, and in the other case does not do so. In other words, in the first form of the 

 experiment the effect of conduction is increased by that of convection, and in the 

 second is not. 



s s 3 



