LAW; ITS DEFINITIONS. 75 



John Herschel, in speaking of this Force, has in- 

 dicated in a passing sentence a few questions out 

 of the many which arise : — " No matter," he says, 

 "from what ultimate causes the power called 

 gravitation originates — be it a virtue lodged in 

 the sun as its receptacle, or be it pressure from 

 without, or the resultant of many pressures, or 

 solicitations of unknown kinds, magnetic or elec- 

 tric, ethers or impulses," * &c. &c. How little 

 we have ascertained in this Law, after all ! Yet 

 there is an immense and an instinctive pleasure 

 in the contemplation of it. To analyse this plea- 

 sure is as difficult as to analyse the pleasure 

 which the eye takes in beauty of form, or the 

 pleasure which the ear takes in the harmonies of 

 sound. And this pleasure is inexhaustible, for 

 these laws of number and proportion pervade all 

 Nature, and the intellectual organs which have 

 been fitted to the knowledge of them have eyes 

 which are never satisfied with seeing, and ears 

 which are never full of hearing. The agitation 

 which overpowered Sir Isaac Newton as the Law 

 of Gravitation was rising to his view in the light 

 * Herschel's Outlines of Astronomy, fifth edition, p. 323. 



