304 EAMBLES OF A NATURALIST. 



works on astronomy ; but of all his labours, that which 

 has rendered his name immortal is the discovery of the 

 laws of the motion of the planets and of the comets round 

 the sun. We will here give these laws, referring our 

 readers to works on astronomy for more ample details. 



1st. The orbits of the planets and the comets are 

 ellipses, of which the sun occupies one of the foci. 



2nd. The area described by the radius vector of a 

 planet or a comet in its movement round the sun, is pro- 

 portional to the time. 



3rd. The squares of the times of the revolution of the 

 planets and comets round the sun are proportional to the 

 cubes of the mean distances from the sun. 



It has been asserted that Kepler was led by accident 

 to these splendid mathematical discoveries, under the in- 

 stigation of those mystic ideas to which he so willingly 

 abandoned himself. We do not know what degree of 

 truth there may be in this allegation, but it is very certain 

 that this great astronomer was moved by deep religious 

 impressions. We possess a proof of this in the beautiful 

 prayer which terminates one of his works, and which has 

 been introduced in the opening part of Buckland's Reli- 

 qiiicB DiluviatKB. It will no doubt afford satisfaction to 

 our readers if we give a translation which has been 

 made of this prayer. 



" Before I leave this table on which I have made all 

 my calculations, I must raise my eyes and my hands 

 towards heaven, and devoutly address my humble prayer 

 to the author of all light. O Lord, by the sublime light 



the famous text in the Book of Joshua, was long held in high esteem 

 amongst theologians. It is now entirely exploded. Tycho Brahe 

 had erected his observatory of Uranibourg, on a little island of the 

 Baltic, which he rendered celebrated by his labours and by several 

 important discoveries. 



