LIB. II. 24, 25. 205 



At vitrum calendare clare ostendit expansionem in 

 aere, et conspicuam, et progredientem, et durantern, 

 neque transeuntem. 



Rursus, exempli gratia, sit natiira inquisita, pondus. 

 Instantia ostensiva ponderis cst argentum vivum 5;} . 

 Omnia enira superat pondere magno intervallo, practer 

 aurum ; quod non multo gravius est. At prsestantior 

 instantia est ad indicandam formam ponderis argentum 

 vivum, quam aurum ; quia aurum solidum est, et con- 

 sistens, quod genus referri videtur ad densum ; et ar 

 gentum vivum liquidum est, et turgens spiritu, at 

 tamen multis partibus exuperat gravitate diamantem, 

 et ea qua; putantur solidissima. Ex quo ostenditur, 

 formam gravis, sive ponderosi, dominari simpliciter in 

 copia materia?, et non in arcta compage 54 . 



XXV. 



Inter prserogativas instantiarum ponemus quarto loco 

 instantias clandestinas, quas etiam instantias crepusculi 

 appellare consuevimus 55 . Ese sunt veluti oppositsc 

 imtantiis ostemivis. Exhibent enim naturam inqui- 

 sitam in infiina virtute, et tanquam in incunabulis, et 

 rudimentis suis ; tentantem, et tanquam primo expe- 



53 This is not a good Instance ; is an excellent one ; and leads 

 for gold, which is heavier than Bacon to the correct result, viz. 

 quicksilver, also becomes fluid by &quot; liquidum et consistens esse no- 

 the application of Heat; and quick- tiones tantum plebeias, &c.&quot; 

 silver is solid at a certain tempera- &quot; This class of Instances is of 

 ture. great use, being, in fact, frequently 



54 &quot; dominari in.&quot; This phrase no other than that of extreme cases, 

 seems to refer to Bacon s name of which, by placing our conclusions, 

 Prcedominantes Instantiaj; &quot; rules as it were, in violent circumstances, 

 over.&quot; try their temper, and bring their 



55 These Clandestine Instances vigour into test.&quot; Herschel s Dis- 

 are the contrary of the last. The course, 193. They will be chiefly 

 &quot; Nature&quot; sought for is in its weak- applicable, then, after our conclusion 

 est and most imperfect state. The has been arrived at. 



illustration of the cohesion of fluids 



