682 COSMOS. 



age of astronomy and mathematics; and in the latter the 

 long series of profound enquirers leading us on to the " all 

 transforming" Leonhard Euler, the year of whose birth, (1 707) 

 is so near that of the death of Jacques Beriiouilli. 



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 

 rather than from the incitement of outward circumstances. 

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

 the planets were now recognised. The pressure of the 

 atmosphere ; the propagation of light, and its refraction and 

 polarisation, were investigated. Mathematical physics were 

 created, and based on a firm foundation. The invention of 

 the infinitesimal calculus characterises the close of the 

 century ; and strengthened by its aid, human understanding 

 has been enabled, during the succeeding century and a half, 

 successfully to venture on the solution of the problems pre- 

 sented by the perturbations of the heavenly bodies ; by the 

 polarisation and interference of the waves of light; by the 

 radiation of heat; by electro-magnetic re-entering cur- 

 rents; by vibrating chords and surfaces; by the capillary 

 attraction of narrow tubes ; and by many other natural phe- 

 nomena. 



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, strictness in 

 the methods and improvements in the instruments of obser- 

 vation 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 labours of 

 these distinguished enquirers are so generally known, that 

 slight references will be sufficient to point out those portions 

 by which they have most brilliantly contributed to the 

 enlargement of cosmical views. 



We have already shown* how the discovery of telescopic 

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

 tion of the universe a power from whose limits we are still 



* See Cosmos, p. 67. 



