NOVUM ORGANUM. 93 



order to generate and superinduce any nature upon a given 

 body: and this not in abstruse, but in the plainest lan 

 guage. 



For instance, if a person should wish to superinduce the 

 yellow colour of gold upon silver, or an additional weight 

 (observing always the laws of matter) or transparency on 

 an opaque stone, or tenacity in glass, or vegetation on a 

 substance which is not vegetable, we must (I say) consider 

 what species of precept or guide this person would prefer. 

 And firstly, he will doubtless be anxious to be shown some 

 method that will neither fail in effect, nor deceive him in 

 the trial of it. Secondly, he will be anxious that the pre 

 scribed method should not restrict him and tie him down 

 to peculiar means, and certain particular methods of acting. 

 For he will, perhaps, be at a loss, and without the power 

 or opportunity of collecting and procuring such means. 

 Now if there be other means and methods (besides those 

 prescribed) of creating such a nature, they will perhaps be 

 of such a kind as are in his power, yet by the confined 

 limits of the precept he will be deprived of reaping any 

 advantage from them. Thirdly, he will be anxious to be 

 shown something not so difficult as the required effect it 

 self, but approaching more nearly to practice. 



We will lay this down, therefore, as the genuine and 

 perfect rule of practice ; &quot; That it should be certain, free, 

 and preparatory, or having relation, to practice.&quot; And this 

 is the same thing as the discovery of a true form. For the 

 form of any nature is such, that when it is assigned the 

 particular nature infallibly follows. It is, therefore, always 

 present when that nature is present, and universally attests 

 such presence, and is inherent in the whole of it. The 

 same form is of such a character, that if it be removed the 

 particular nature infallibly vanishes. It is, therefore, ab 

 sent whenever that nature is absent, and perpetually testi 

 fies such absence, and exists in no other nature. Lastly, 

 the true form is such, that it deduces the particular nature 

 from some source of essence existing in many subjects, and 

 more known (as they term it) to nature, than the form 

 itself.* Such then is our determination and rule with 



* Thus, to adopt Bacon s own illustration, motion is a property common to 

 many subjects, from which must be deduced the form of heat, by defining a 

 particular genus of motion convertible with heat. See the First Vintage in 

 Aphorism 20 below. 



