108 OF THE ADVANCEMENT OF LEARNING 



subject some axioms or parts of natural philosophy, 

 and considereth quantity determined, as it is auxiliary 

 and incident unto them. For many parts of nature 

 can neither be invented with sufficient subtilty, nor 

 demonstrated with sufficient perspicuity, nor accom- 

 modated unto use with sufficient dexterity, without 

 the aid and intervening of the mathematics ; of which 

 sort are perspective, music, astronomy, cosmography, 

 architecture, enginery, and divers others. In the 

 mathematics I can report no deficience, except it be 

 that men do not sufficiently understand the excellent 

 use of the pure mathematics, in that they do remedy 

 and cure many defects in the wit and faculties in- 

 tellectual. For if the wit be too dull, they sharpen it ; 

 if too wandering, they fix it ; if too inherent in the 

 sense, they abstract it. So that as tennis is a game 

 of no use in itself, but of great use in respect it maketh 

 a quick eye and a body ready to put itself into all 

 postures ; so in the mathematics, that use which is 

 collateral and intervenient is no less worthy than that 

 which is principal and intended. And as for the 

 mixed mathematics, I may only make this prediction, 

 that there cannot fail to be more kinds of them, as 

 nature grows further disclosed. Thus much of natural 

 science, or the part of nature speculative. 



3. For natural prudence, or the part operative of 

 natural philosophy, we will divide it into three parts, 

 experimental, philosophical, and magical : which three 

 parts active have a correspondence and analogy with 

 the three parts speculative, natural history, physic, 

 and metaphysic. For many operations have been 

 invented, sometime by a casual incidence and occur- 

 rence, sometimes by a purposed experiment : and of 

 those which have been found by an intentional experi- 

 ment, some have been found out by varying or ex- 

 tending the same experiment, some by transferring 

 and compounding divers experiments the one into 

 the other, which kind of invention an empiric may 

 manage. Again by the knowledge of physical causes 

 there cannot fail to follow many indications and desig- 



