NOVUM ORGANUM 239 



(as far as regards any great difference between the true and 

 apparent time), was subsequently 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 consider 

 able interval of time between the reality and the appear 

 ance, the images would often be interrupted and confused 

 by clouds formed in the meantime, and similar disturb 

 ances 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 

 measure of motions and actions which must be inquired 

 into, for this latter is of great use and application. We 

 perceive that the flame of firearms 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 



the earth, the necessity of time for the propagation of light. The idea occurred 

 to Dominic Cassini as well as Bacon, but both allowed the discovery to slip out 

 of their hands. Ed. 



