

THE UNIVERSE. DISCOVERIES IN THE CELESTIAL SPACES. 323 



ing terrestrial natural events, such as earthquakes in coun- 

 tries where they are rarely felt, the outbreak of volcanoes 

 after long periods of repose, the rushing sound of aerolites 

 which traverse our atmosphere and become suddenly heated 

 in it, awaken for a time a lively interest in problems which 

 appear even more mysterious to persons in general than to 

 dogmatising philosophers. 



In the foregoing remarks on the influence exerted by the 

 direct visible contemplation of particular heavenly bodies, I 

 have named Kepler more particularly, for the sake of re- 

 calling how, in this great, richly gifted, and extraordinary 

 man, the love for imaginative combinations was united with 

 a remarkable talent for observation, a grave and severe 

 method of induction, a courageous and almost unexampled 

 perseverance in calculation, and a depth of mathematical 

 thought which, displayed in his Stereometria doliorum, exer- 

 cised a happy influence on Fermat, and through him on the 

 invention of the infinitesimal calculus. ( 495 ) The possessor 

 of such a mind ( 496 ) was pre-eminently suited, by the richness 

 and mobility of his ideas, and even by the boldness of the 

 cosmological speculations which he hazarded, to promote 

 and animate the movement which carried the 17th century 

 uninterruptedly forward towards the attainment of its exalted 

 object, the enlarged contemplation of the universe. The 

 many comets visible to the naked eye from 1577 to the 

 appearance of Bailey's comet in 1607 (eight in number), 

 and the apparition, almost within the same period, of the 

 three new stars already spoken of, led to speculations in 

 which these heavenly bodies were viewed as originating from, 

 or being formed out of, a cosmical vapour filling the regions 

 of space. Kepler, like Tycho Brahe, believed the new stars 



