238 NOVUM ORGANUM 



take place in times the sums of which can be computed. 

 With regard to heat, we see that boys in winter bathe 

 their hands in the flame without being burned; and con 

 jurers, by quick and regular movements, overturn vessels 

 filled with wine or water, and replace them without spilling 

 the liquid, with several similar instances. The compres 

 sion, expansion and eruption of several bodies, take place 

 more or less rapidly, according to the nature of the body 

 and its motion, but still in definite moments. 



In the explosion of several cannon at once (which are 

 sometimes heard at the distance of thirty miles), the sound 

 of those nearest to the spot is heard before that of the most 

 distant. Even in sight (whose action is most rapid), it is 

 clear that a definite time is necessary for its exertion, 

 which is proved by certain objects being invisible from 

 the velocity of their motion, such as a musket-ball; for 

 the flight of the ball is too swift to allow an impression 

 of its figure to be conveyed to the sight. 



This last instance, and others of a like nature, have 

 sometimes excited in us a most marvellous doubt, no less 

 than whether the image of the sky and stars is perceived 

 as at the actual moment 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 ob 

 served by astronomers in parallaxes. It appeared so in 

 credible 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. 78 That doubt, however 



78 Romer, a Danish astronomer, was the first to demonstrate, by connecting 

 the irregularities of the eclipses of Jupiter s satellites with their distances from 



