440 BACON 



of its existence, or rather a little after, and whether there is not 

 (with regard to the visible appearance of the heavenly bodies) a 

 true and apparent time, as well as a true and apparent place, 

 which is observed by astronomers in parallaxes. It appeared so 

 incredible to us, that the images or radiations of heavenly bodies 

 could suddenly be conveyed through such immense spaces to the 

 sight, and it seemed that they ought rather to be transmitted in 

 a definite time. That doubt, however (as far as regards any 

 great difference between the true and apparent time), was sub- 

 sequently completely set at rest, when we considered the infinite 

 loss and diminution of size as regards the real and apparent 

 magnitude of a star, occasioned by its distance, and at the same 

 time observed at how great a distance (at least sixty miles) 

 bodies which are merely white can be suddenly seen by us. For 

 there is no doubt, that the light of the heavenly bodies not only 

 far surpasses the vivid appearance of white, but even the light 

 of any flame (with which we are acquainted) in the vigor of its 

 radiation. The immense velocity of the bodies themselves, 

 which is perceived in their diurnal motion, and has so astonished 

 thinking men, that they have been more ready to believe in the 

 motion of the earth, renders the motion of radiation from them 

 (marvellous as it is in its rapidity) more worthy of belief. That 

 which has weighed most with us, however, is, that if there were 

 any considerable interval of time between the reality and the 

 appearance, the images would often be interrupted and confused 

 by clouds formed in the mean time, and similar disturbances of 

 the medium. Let this suffice with regard to the simple measures 

 of time. 



It is not merely the absolute, but still more the relative meas- 

 ure of motions and actions which must be inquired into, for 

 this latter is of great use and application. We perceive that 

 the flame of fire-arms is seen sooner than the sound is heard, 

 although the ball must have struck the air before the flame, 

 which was behind it, could escape : the reason of which is, that 

 light moves with greater velocity than sound. We perceive, 

 also, that visible images are received by the sight with greater 

 rapidity than they are dismissed, and for this reason, a violin 

 string touched with the finger appears double or triple, because 

 the new image is received before the former one is dismissed. 

 Hence, also, rings when spinning appear globular, and a lighted 

 torch, borne rapidly along at night, appears to have a tail. Upon 

 the principle of the inequality of motion, also, Galileo attempted 

 an explanation of the flood and ebb of the sea, supposing the 

 earth to move rapidly, and the water slowly, by which means the 

 water, after accumulating, would at intervals fall back, as is 

 shown in a vessel of water made to move rapidly. He has, how- 

 ever, imagined this on data which cannot be granted (namely, 



