ii NO ELEMENTS IN ISOLATION 209 



failed to be convinced by it. Bruno's very errors are 

 interesting. Fire for example, far from being the 

 outermost, lightest, subtlest element, was regarded by 

 him as a body of which the substance, (light and heat 

 being accidents) was water mixed with earth ; * and in 

 general, he maintained, no element was ever found in 

 isolation. As to the supposed coldness of the central 

 element, the earth, he believed, again anticipating 

 future discoveries, that the centre of the earth was not 

 cold, but hot, the source of terrestrial warmth ; but the 

 theory loses something of its value, scientifically, from 

 the imagined vitality of the planet, by which it is 

 supported. 2 It was natural that the coincidence of 

 contraries should be brought to do duty against the 

 maxim on which the Aristotelian view was really based 

 namely, that contraries tend to rest at the greatest 

 possible distance from one another, against which Bruno 

 marshalled a whole army of facts. Away from the 

 shadow of the earth there was perhaps no light but 

 that of the sun, too strong for our eyes, for the 

 daylight arose from a mixture of the light of the 

 sun and the darkness of the earth ; we could see 

 other colours by it, for the reason that they were 

 similarly composed mixtures of light and darkness. 

 The heat of the sun also was only bearable when 

 tempered by the coolness of the earth or other 

 planets. The body of the earth, great as it is, 

 can bear this heat only through its swift revolution. 

 As to the objection that if the earth moved we 

 should feel its motion, Bruno remarked that when 

 we are carried in a smoothly and continuously moving 

 vehicle, not striking against any object, we do not 

 perceive that we are moving, except by comparison with 



1 Op.Lat.Li. p. 353. a P. 354.. 



P 



