ADVANCEMENT OF LEARNING 47 



artificial: whence many writers of natural history think they 

 perform notably, if they give us the history of animals, plants, or 

 minerals, without a word of the mechanic arts. A further mis- 

 chief is to have art esteemed no more than an assistant to nature, 

 so as to help her forwards, correct or set her free, and not to bend, 

 change, and radically affect her; whence an untimely despair 

 has crept upon mankind; who should rather be assured that 

 artificial things differ not from natural in form or essence, but 

 only in the efficient : for man has no power over nature in any- 

 thing but motion, whereby he either puts bodies together, or 

 separates them. And, therefore, so far as natural bodies may 

 be separated or conjoined, man may do anything. Nor matters 

 it, if things are put in order for producing effects, whether it be 

 done by human means or otherwise. Gold is sometimes purged 

 by the fire, and sometimes found naturally pure: the rainbow 

 is produced after a natural way, in a cloud above ; or made arti- 

 ficially, by the sprinkling of water below. As nature, there- 

 fore, governs all things by means I. of her general course; 

 2. her excursion ; and 3. by means of human assistance ; these 

 three parts must be received into natural history, as in some 

 measure they are by Pliny. 



The first of these parts, the history of creatures, is extant in 

 tolerable perfection ; but the two others, the history of monsters 

 and the history of arts, may be noted as deficient. For I find 

 no competent collection of the works of nature digressing from 

 the ordinary course of generations, productions, and motions ; 

 whether they be singularities of place and region, or strange 

 events of time and chance ; effects of unknown properties, or 

 instances of exceptions to general rules. We have indeed many 

 books of fabulous experiments, secrets, and frivolous impos- 

 tures, for pleasure and strangeness ; but a substantial and well- 

 purged collection of heteroclites, or irregularities of nature, 

 carefully examined and described, especially with a due rejec- 

 tion of fable and popular error, is wanting : for, as things now 

 stand, if false facts in nature be once on foot, through the neg- 

 lect of examination, the countenance of antiquity, and the use 

 made of them in discourse, they are scarce ever retracted. 



The design of such a work, of which we have a precedent in 

 Aristotle, is not to content curious and vain minds, but 

 I. to correct the depravity of axioms and opinions, founded upon 

 common and familiar examples ; and 2. to show the wonders of 



