NOVUM ORGANUM 163 



the form of whiteness, namely, that two bodies, in them 

 selves more or less transparent (as air and water, or air and 

 glass), when brought into contact in minute portions, ex 

 hibit whiteness from the unequal refraction of the rays 

 of light. 



But here we must also give an example of the danger 

 and caution of which we spoke; for instance, it will readily 

 occur to an understanding perverted by efficients, that air is 

 always necessary for producing the form of whiteness, or 

 that whiteness is only generated by transparent bodies, which 

 suppositions are both false, and proved to be so by many 

 exclusions; nay, it will rather appear (without any particu 

 lar regard to air or the like), that all bodies which are even 

 in such of their parts as affect the sight exhibit transparency, 

 those which are uneven and of simple texture whiteness, those 

 which are uneven and of compound .but regular texture all 

 the other colors except black, but those which are uneven 

 and of a compound irregular and confused texture exhibit 

 blackness. An example has been given, therefore, of an in 

 stance migrating toward generation in the required nature of 

 whiteness. An instance migrating toward corruption in the 

 same nature is that of dissolving froth or snow, for they lose 

 their whiteness and assume the transparency of water in its 

 pure state without air. 



Nor should we by any means omit to state, that under 

 migrating instances we must comprehend not only those 

 which pass toward generation and destruction, but also those 

 which pass toward increase or decrease, for they, too, assist 

 in the discovery of the form, as is clear from our definition 

 of a form and the Table of Degrees. Hence paper, which is 

 white when dry, is less white when moistened (from the ex 

 clusion of air and admission of water), and tends more to 



