122 OF THE ADVANCEMENT OF LEARNING. [VIII. 2. 



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 per 

 spicuity, nor accommodated unto use with sufficient dex 

 terity, without the aid and intervening of the mathematics ; 

 of which sort are perspective, music, astronomy, cosmo 

 graphy, 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 intellectual. 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 na 

 tural philosophy, we will divide it into three parts, experi 

 mental, 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 occurrence, sometimes by a pur 

 posed experiment : and of those which have been found 

 by an intentional experiment, some have been found out 

 by varying or extending the same experiment, some by 



