302 EPOCHS IN THE HISTORY OF THE CONTEMPLATION OP 



matical thought. The laws that regulate the fall of bodies, 

 and the planetary motions, were recognised ; the pressure of 

 the atmosphere, the propagation of light, and its refraction and 

 polarisation, were investigated. Mathematico-physical science 

 was created, and established on firm foundations. The in- 

 vention of the infinitesimal calculus marks the close of the 

 century ; and, reinforced by its aid, the human intellect has 

 been enabled, in the succeeding hundred and fifty years, to 

 attempt successfully the solution of problems presented by 

 the perturbations of the heavenly bodies, by the polarisation 

 and interference of the waves of light, by radiant heat, by 

 the electro-magnetic re-entering currents, by vibrating chords 

 and surfaces, by the capillary attraction of tubes of small 

 diameter, and by so many other natural phenomena. 



In this world of thought the work proceeds uninter- 

 ruptedly, and its different portions lend to each other mu- 

 tual support. No earlier fruitful germ is stifled. We see 

 increase, simultaneously, the abundance of materials, the 

 strict accuracy of methods, and the perfection of instruments. 

 T propose to limit myself principally to the consideration of 

 the 17th century, the age of Kepler, Galileo, and Bacon, of 

 Tycho Brahe, Descartes, and Huygens, of Eermat, Newton, 

 and Leibnitz. "What they have done is so generally known, 

 that slight indications will suffice to point out through what 

 part of their achievements they have more especially contri- 

 buted to the enlargement of cosmical views. 



We have already shewn ( 459 ) how, by the discovery of 

 telescopic vision, there was lent to the eye, the organ of 

 the sensuous contemplation of the visible universe, a powef 

 of which we are yet far from having reached the limit, but 

 of which the first feeble commencement (magnifying hardly 



