Dr Olbers on the Transparency of Space. 143 



mited reason is unable to procure for us any certainty on the 

 subject. Other regions of space may contain other creations 

 than suns, planets, comets and light ; creations of which we can 

 have no idea. Halley has laboured to produce a proof of the 

 innumerable multitude of suns. " If their number were not in- 

 finite,"" says he, " there would be found in the space which they 

 occupy, a point which would be the centre of gravity of the ge- 

 neral system, and towards which all the bodies of the universe 

 would necessarily be precipitated, with a continually increasing 

 motion. It is only because the universe is infinite, that every 

 thing remains in equilibrium." Halley seems to have only had 

 gravitation in view here, and he says nothing of the power of 

 projection. However, the very motion which appears to be pro- 

 per to these stars, would tend to demonstrate that they are ani- 

 mated with a power of projection. This itself would suffice to 

 shew the insufficiency of the reasoning employed by Halley, 

 against whom there are besides many other charges. 



However, it remains not the less probable, that the beauti- 

 ful order which we observe extending as far as our faculty of 

 sight can penetrate, reigns equally through all space ; and we 

 have only to search if there exist other reasons in nature to 

 induce us to abandon this opinion. Here a very important ob- 

 jection presents itself. If there really be suns in the whole of 

 space, and to infinity, and if they are placed at equal distances 

 from each other, or grouped into systems like that of the Milky 

 Way, their number must be infinite, and the whole vault of hea- 

 ven should appear as bright as the sun ; for every line which 

 may be supposed to emanate from our eye towards the sky, 

 would necessarily meet a fixed star, and thus every point of the 

 sky would bring to us a ray of sideral, or which is the same 

 thing, of solar light. 



There is no need of saying that observation contradicts such 

 a deduction. Halley denies this consequence of the infinite 

 number of fixed stars, but for reasons which are altogether er- 

 roneous. He evidently confounds the apparent magnitudes 

 with the real magnitudes ; and it is only thus that he can ad- 

 vance that the number of the fixed stars increases, it is true, as 

 the square of their distances, but that the intervals which sepa- 

 rate them increase as the double of this square. This is an 



