302 cosmos. 



the telescope, through which man may be said to have taken 

 possession of a considerable portion of the heavens. The ap- 

 plication of a newly-created organ an instrument possessed 

 of the power of piercing the depths of space calls forth a new 

 world of ideas. Now began a brilliant age of astronomy and 

 mathematics ; and in the latter, the long series of profound 

 inquirers, leading us on to the " all transforming" Leonhard 

 Euler, the year of whose birth (1707) is so near that of the 

 death of Jacques Bernouilli. 



A few names will suffice to give an idea of the gigantic 

 strides with* which, the human mind advanced in the seven- 

 teenth century, especially in the development of mathematical 

 induction, under the influence of its own subjective force rath- 

 er than from the incitement of outward circumstances. The 

 laws which control the fall of bodies and the motions of the 

 planets were now recognized. The pressure of the atmosphere ; 

 the propagation of light, and its refraction and polarization, 

 were investigated. Mathematical physics were created, and 

 based on a firm foundation. The invention of the infinitesi- 

 mal calculus characterizes the close of the century ; and, 

 strengthened by its aid, human understanding has been ena- 

 bled, during the succeeding century and a half, successfully to 

 venture on the solution of the problems presented by the per- 

 turbations of the heavenly bodies ; by the polarization and in- 

 terference of the waves of light ; by the radiation of heat ; by 

 electro-magnetic re-entering currents ; by vibrating chords 

 and surfaces ; by the capillary attraction of narrow tubes ; and 

 by many other natural phenomena. 



Henceforward the work in the world of thought progresses 

 uninterruptedly, each portion continually contributing its aid 

 to the remainder. None of the earlier germs are stifled. 

 With the abundance of the materials to be elaborated, strict- 

 ness in the methods and improvements in the instruments of 

 observation are simultaneously increased. We will here limit 

 ourselves more especially to the seventeenth century, the age 

 of Kepler, Galileo, and Bacon, of Tycho Brahe, Descartes, 

 and Huygens, of Fermat, Newton, and Leibnitz. The labors 

 of these distinguished inquirers are so generally known, that 

 slight references will be sufficient to point out those portions 

 by which they have most brilliantly contributed to the en- 

 largement of cosmical views. 



We have already shown* how the discovery of telescopic 

 vision gave to the eye the organ of the sensuous contempla* 

 * See Cosmos, vol.. i., p. 83. 



