214 NICOLAUS STENO 



again and again inculcates concerning maxims of morality; he 

 says that those are the best maxims of morality which are 

 p. 10. common, which are of the people, which all of every school 

 proclaim, Peripatetics, Academics, Stoics, and Cynics. And 

 certainly those statements of the fundamental facts of nature 

 cannot fail to be best which are common, which are accepted 

 of the people, which all of every school are held to acknowl- 

 edge, both those who in everything are desirous of novelty, and 

 those who are devoted to ancient doctrines. 



I do not determine, therefore, whether the particles of a 

 natural body, can or cannot undergo change, as its form does ; 

 whether there are or are not minute interstices; whether in 

 those particles there is present, besides extension and hardness, 

 something else unknown to us ; for these expressions are not 

 of common acceptance, and it is a weak argument to deny that 

 there is anything else in a certain object because I do not 

 discern anything else in it. 



I do assert, however, without hesitation : 



1. That a natural body is an aggregate of imperceptible 

 particles which is subject to the operation of forces proceeding 

 from the magnet, fire, and sometimes light also ; in whatever 

 way, indeed, passages may be found, whether between the par- 

 ticles, or in the particles themselves, or in both. 



2. That a solid differs from a fluid in that in a fluid the 

 imperceptible particles are in constant motion, and mutually 

 withdraw from one another; while in a solid, although the 

 imperceptible particles may sometimes be in motion, they 

 hardly ever withdraw from one another so long as that solid 

 remains a solid and intact. 



P. 11. 3. That while a solid body is being produced, its particles 

 are in motion from place to place. 



4. That as yet we know of nothing in the nature of matter 

 by the aid of which the principle of motion, and the perception 

 of motion, can be explained; but that the determination of 

 natural motions can be altered by three causes : 



(i) By the motion of a fluid permeating all bodies ; and we 



safy, useful, and pleasant, and of Ep., I2. 11, where 'the best things' are said to be 'com- 

 mon ' : quae optima sunt, esse communia. 



