244 On the Application of Telescopes 



poetic style, which we could not expect from his pen nor 

 from the subject. T shall do little else than translate it, and 

 the following is the way in which he explains himself*. 



" One night, about the end of March 1635, I amused 

 myself with my telescope, and was considering Jupiter and 

 his satellites, musing profoundly, and thinking what might 

 be the use to which these small planets were destined, when, 

 all at once, a celestial messenger came on wing, presented 

 himself to me, and held this discourse : ' Why fatiguest 

 thou thine eyes uselessly in observing the moon, the sun, 

 and .lupiter, with this instrument? Leave this amusement 

 to others, and apply thyself to things more useful, and to 

 which thou art destined : if thou followest my advice, a far 

 greater glory is reserved for thee, since thou shalt see in 

 broad day-light the planets and the principal stars, which 

 no mortal has hitherto been able to perceive unless during 

 the night : this will give thee the most certain means of 

 establishing the prmcipal elements of astronomy : ' and af- 

 ter having said these few words to me he disappeared. His 

 discourse could not be eflaced from my memory, and I had 

 no more rest until J had found by what means I might see 

 the planets and bright stars during the day-time; and I 

 applied with so much more ardour, as I remembered, under 

 some particular circumstances, to have seen Venus with the 

 naked eye whilst the sun was very high above the horizon. 

 This is tlie method I pursued. 



" I affixed a telescope of a foot and a half to the index 

 of one of my instruments, which served it as a support; 

 and I placed this apparatus in the western window of my 

 room, in order that the brightness of the rising sun might 

 not dazzle me. Some time before day-light, whilst the 

 bright stars were yet visible, I put Arcturus in my tele- 

 scope, and kept it there almost until the rising of the 

 sun ; remarking with pleasure, that 1 yet saw it distinctly 

 in the telescope, a long time after the brightness of the day 

 made it disappear to the naked eye : a cloud covered it at 

 this moment, and when it was passed, I could not with 

 every endeavour find it ao-ain. This accident distressed me; 

 hut I was patient, well kncnvinsr that had it not been for 

 this clouc, I should have been able to have seen the star 

 much longer. Next morning before day-light, the sky 

 being very clear, I got Arcturus in my telescope, and kept 

 ' it there until I saw the light of the rising sun enliiihtcnintj 



♦ Scien. Longit. pars vi. p. CIO & seq. i 



thC' 



