to explain and defend it. Some of the reasons on 

 this system is ' founded are, . 1. This is most simple and 

 agreeable TO the whole tenure of nature : tor by the t\vo 

 motions of the earth,- all the phenomena of the heavens 

 are resolved,, which on any of the other hypothesis are 

 .utterly inexplicable. 2. It is more rational to suppose 

 the earth moves round the sun, than -that the huge bodies 

 of the planets and of the sun itself, and the immense 

 firmament of stars, should all move round the 'inconsider- 

 able body of earth every four and twenty hours. 3. The 

 earth's moving round the sun is agreeable to that general 

 harmony and universal law, -which ail other moving 

 bodies of the system observe, namely, that the squares 

 ; of the periodical times are as the cubes of the distances. 

 But if the sun move round the earth, that law is de- 

 stroyed, and the general order and symmetry of nature 

 interrupted ; = because according to that law, the sun 

 would be so far from revolving about the earth jn 365 

 clays, that it would, require not less than 5106 years, to 

 ..finish one revolution. 4. The sun is the fountain of 

 light and heat, which it darts tjiroiurh the *v hole system, 

 and therefore it ought to be placed, as the heart in the 

 centre, that so all the planets may at all times have them, 

 in an uniform and equal manner. .5. If the sun.be 

 placed in the centre of tire system, we have then the ra- 

 tional hypothesis of the planets being all moved about 

 the sun, .by the universal law of gravity : and every thing 

 .will answer to that law; but otherwise we are wholly ia 

 the dark. 6. But we need not rely upon corj jactures. 

 : \Ve have demonstrative proofs, that the sun possesses the 

 centre, and that the planets move round it, in the order 

 above mentioned. For example. Mercury and Venus 

 are ever observed to have two conjunctions with the sun, 

 but no opposition, which could not happen unless the 

 orbits of those planets lay wJthiitthe, orbit of the earth, 

 A !(i in the same manner it may be demonstrated, that 

 th * orbits ot Mars, Jupiter, and Saturn, lie. without tue 

 orbit of the earth. 



7, After Copernicus, came Tycho Brahe, a noble 



