THE SUCCESSORS OF GALILEO 



as to strike upon the organs of sight, and cause the 

 sensation we call color; and that this latter is the 

 more proper acceptation of the word color will appear 

 hereafter. And indeed it is the light itself, which 

 after a certain manner, either mixed with shades or 

 otherwise, strikes our eyes and immediately produces 

 that motion in the organ which gives us the color of 

 an object." fl 



In examining smooth and rough surfaces to deter- 

 mine the cause of their color, he made use of the 

 microscope, and pointed out the very obvious example 

 of the difference in color of a rough and a polished 

 piece of the same block of stone. He used some 

 striking illustrations of the effect of light and the 

 position of the eye upon colors. "Thus the color of 

 plush or velvet will appear various if you stroke part 

 of it one way and part another, the posture of the 

 particular threads in regard to the light, or the eye, 

 being thereby varied. And 'tis observable that in a 

 field of ripe corn, blown upon by the wind, there will 

 appear waves of a color different from that of the 

 rest of the corn, because the wind, by depressing 

 some of the ears more than others, causes one to 

 reflect more light from the lateral and strawy parts 

 than another." 7 His work upon color, however, as 

 upon light, was entirely overshadowed by the work 

 of his great fellow-countryman Newton. 



Boyle's work on electricity was a continuation of 

 Gilbert's, to which he added several new facts. He 

 added several substances to Gilbert's list of " electrics," 

 experimented on smooth and rough surfaces in excit- 

 ing of electricity, and made the important discovery 



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