CAPILLARY ATTRACTION. 255 



small capillary tubes, through which the blood 

 is circulated by the same power which causes 

 universal attraction. 



The subject of capillary attraction has been 

 laboriously investigated by many of the most 

 distinguished votaries of science, for the last 150 

 years ; but without any attempt to explain the 

 cause of the phenomena ; if we except a single 

 suggestion of Newton, contained in his letter to 

 Boyle, concerning the cetlier. He there refers 

 capillarity to the same agent which causes men- 

 struums to dissolve solids, a most important 

 hint, for which his successors have not given him 

 any credit. It must, however, be acknowledged, 

 that he never gave a satisfactory explanation of 

 what causes solution. Still, his views were more 

 just and comprehensive than those of the present 

 day. That he also referred vital attraction to the 

 same cause which produces ordinary capillary 

 attraction, is evident from the following observa- 

 tion : " The same principle which causes a sponge 

 to suck in water, causes the glands in animal 

 bodies to suck in the various juices from the 

 blood, according to their several natures and dis- 

 positions." (Opticks, page 367.) 



In the time of Newton, it was ascertained ex- 

 perimentally by Hawkesbee, 



1. That water rises to the same height in 

 capillary glass tubes of equal diameter, whether 

 the tubes be thin or thick. 



