tOOK tt.] St'IiJt*2.*CTlVE iNSTAJfCEg. 601 



our sphere, for lliese qualities cannot be predicated of any bodies 

 below the heavens, or above the interior of the earth. Secondly, 

 to our general propositions as to any concrete, whether affirmative 

 or negative, we should subjoin the concretes which appear to 

 approach nearest to the non-existing substances j sucn as the 

 most gentle or least-burning flames in heat, or gold in incor- 

 ruptibility, since it approaches nearest to it. Por they all serve 

 to show the limit of existence and non-existence, and circumscribe 

 forms, 80 that they cannot wander beyond the conditions of 

 matter. 



XXXIY. In the twelfth rank of prerogative instances, we 

 will class those subjunctive instances, of which we spoke in the 

 last aphorism, and which we are also wont to call instances of 

 extremity or limits ; for they are not only serviceable when sub- 

 joined to fixed propositions, but also of themselves and from their 

 own nature. They indicate with, sufficient precision the real 

 divisions of nature, and measures ol things, and the " how far " 

 nature effects or allows of anything, and her passage thence to 

 something else. Such are gold in weight, iron in hardness, the 

 whale in the size of animals, the dog in smell, the flame of gun- 

 powder in rapid expansion, an,d others of a like nature. Nor are 

 we to pass over the extremes in defect, as well as in abundance, 

 as spirits of wine in weight, the touchstone in softness, the worms 

 upon the skin in the size of animals, and the like. 



XXXV. In the thirteenth rank of- prerogative instances, we 

 will place those of alliance or union. They are such as mingle 

 and unite natures held to be heterogeneous, and observed and 

 marked as such in received classifications. 



These instances show that the operation and effect, which is 

 considered peculiar to some one of such heterogeneous natures, 

 may also be attributed to another nature styled heterogeneous, 

 80 as to prove that the difference of the natures is not real nor 

 essential, but a mere modification of a common nature. They 

 are very serviceable, therefore, in elevating and carrying on the 

 mind, ftom differences to genera, and in removing those phan- 

 toms and images of things, which meet it in disguise in concrete 

 substances. 



For example : let the required nature be heat. The classi- 

 fication of heat into three kinds, that of the celestial bodies, that 

 of animals, and that of fire, appears to be settled and admitted ; 

 and these kinds of heat, especially one of them compared with 

 the other two, are supposed to be different, and clearly hetero- 

 geneous in their essence and species, or specific nature, since the 

 heat of the heavenly bodies and of animals generates and che- 

 rishes, whilst that of fire corrupts and destroys. We have an 

 instance of alliance, then, in a very common experiment, that of 

 a vine branch admitted into a building where there is a constant 



