NOVUM ORGANUM. 143 



For example : let the required nature be heat. Flame is 

 an accompanying instance. For in water, air, stone, metal, 

 and many other substances, heat is variable, and can ap 

 proach or retire, but all flame is hot, so that heat always 

 accompanies the concretion of flame. We have no hostile 

 instance of heat. For the senses are unacquainted with 

 the interior of the earth, and there is no concretion of any 

 known body which is not susceptible of heat. 



Again, let solidity be the required nature. Air is an 

 hostile instance. For metals may be liquid or solid, so may 

 glass ; even water may become solid by congelation, but air 

 cannot become solid or lose its fluidity. 



With regard to these instances of fixed propositions, there 

 are two points to be observed, which are of importance. 

 First, that if there be no universal affirmative or negative, 

 it be carefully noted as not existing. Thus, in heat, we 

 have observed that there exists no universal negative, in 

 such substances at least as have come to our knowledge. 

 Again, if the required nature be eternity or incorruptibility, 

 we have no universal affirmative within our sphere, for these 

 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 affirma 

 tive or negative, we should subjoin the concretes which 

 appear to approach nearest to the non-existing substances ; 

 such as the most gentle or least burning flames in heat, or 

 gold in incorruptibility since it approaches nearest to it. 

 For they all serve to show the limit of existence and non- 

 existence, and circumscribe forms, so that they cannot 

 wander beyond the conditions of matter. 



34. 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 ser 

 viceable when subjoined to fixed propositions, but also of 

 themselves and from their own nature. They indicate with 

 sufficient precision the real divisions of nature, and mea 

 sures of things, and the &quot; How far&quot; nature effects or allows 

 of any thing, 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 gunpowder 

 in rapid expansion, and 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. 



