ASTRONOMICAL HISTORY. 165 



lish such a system with the sun for its centre. And the 

 consent of later ages and of antiquity has rather anticipated 

 and sanctioned that idea than not. For the supposition of 

 the earth s motion is not new, but, as we have already said, 

 echoed from the ancients ; but that of the sun being the 

 centre of the world, and immoveably fixed, is entirely new, 

 (if we except the supposed mention of it in an ill translated 

 verse) and was first promulgated by Copernicus. 



A third question follows with respect to the depth of tha 

 system, not that any exact measure of it can be taken, but 

 that it may be set down for certain: whether the starry 

 heaven is, so to speak, one region, or as it is commonly 

 expressed, orb, or whether the stars which are denominated 

 fixed, are higher than the others, in a sort of abysmal pro 

 found ? For it cannot be that they are of equal height, if 

 we understand this strictly ; for the stars are undoubtedly 

 not arranged as in a plane, having a certain measureable 

 size on a superficies, like spots or embedded gems, but 

 are entire globes, large, and lying deep in the profound. 

 Wherefore when they are found of such disproportionate 

 magnitude, it is by all means requisite that some of them 

 should come out more than others, either upwards or down 

 wards; nor can it be that either in the upper or lower part 

 of them, they are joined in one continuous layer. Were 

 this true of certain portions of the stars, it would be rash to 

 assert it of them in their aggregate, that the stars are not 

 higher placed the one than the other ; but even though 

 this were true, still we can affirm a defined and very per 

 ceptible depth or thickness of that region which is called 

 the sphere or starry heaven, containing such projecting 

 points and varieties of altitude ; for we see, from the apo 

 gees and perigees of the planets, that there belongs to their 

 several heavens a certain distinguishable depth through 

 which they mount and descend. But that question only 

 regards this point, whether there are stars one above 

 another as planet above planet, and, as it were, in different 

 orbits ? And that again is in like manner collateral to the 

 other question, regarding the motion or condition of the 

 earth. For if the stars revolve with a diurnal motion about 

 the earth, since they are all carried with the like celerity, 

 and as it were with the one impulse ; and since it is 

 plainly apparent that each of the planets, as it varies in 

 height or lowness of position, so it also varies in rapidity 

 or slowness of motion ; it is probable that stars, equal in 

 the swiftness of their revolution, are placed in one region of 



