VOL. LXXXV.] PHILOSOPHICAL TRANSACTIONS. 401 



other cause can we so probably account for their periodical changes? Again, 

 our sun has spots on its surface. So has the star Algol; and so have the stars 

 already named; and probably every star in the heavens. On our sun these spots 

 are changeable. So they are on the star o Ceti ; as evidently appears from the 

 irregularity of its changeable lustre, which is often broken in upon by accidental 

 changes, while the general period continues unaltered. The same little devia- 

 tions have been observed in other periodical stars, and ought to be ascribed to 

 the same cause. But if stars are suns, and suns are inhabitable, we see at once 

 what an extensive field for animation opens itself to our view. 



It is true that analogy may induce us to conclude, that since stars appear to be 

 suns, and suns, according to the common opinion, are bodies that serve to en- 

 lighten, warm, and sustain a system of planets, we may have an idea of number- 

 less globes that serve for the habitation of living creatures. But if these suns 

 themselves are primary planets, we may see some thousands of them with our 

 own eyes, and millions by the help of telescopes; when at the same time, the 

 same analogical reasoning still remains in full force, with regard to the planets 

 which these suns may support. In this place, I may however take notice that, 

 from other considerations, the idea of suns or stars being merely the supporters 

 of systems of planets, is not absolutely to be admitted as a general one. Among 

 the great number of very compressed clusters of stars, given in my catalogues, 

 there are some which open a different view of the heavens to us. The stars in 

 them are so very close together, that notwithstanding the great distance at which 

 we may suppose the cluster itself to be, it will hardly be possible to assign any 

 sufficient mutual distance to the stars composing the cluster, to leave room for 

 crowding in those planets, for whose support these stars have been, or might be, 

 supposed to exist. It should seem therefore highly probable that they exist for 

 themselves; and are in fact only very capital, lucid, primary planets, connected 

 together in one great system of mutual support. 



As in this argument I do not proceed on conjectures, but have actual observa- 

 tions in view, I shall mention an instance in the clusters, N° 26, 28, and 35, 

 class 6, of my catalogue of nebulae, and clusters of stars in the Phil. Trans, vol. 

 79. The stars in them are so crowded, that I cannot conjecture them to be at a 

 greater apparent distance from each other than 5"; even after a proper allowance 

 for such stars, as on a supposition of a globular form of the cluster, will inter- 

 fere with each other, has been made. Now if we would leave as much room be- 

 tween each of these stars as there is between the sun and Sirius, we must place 

 these clusters 42104 times as far from us as that star is from the sun. But in 

 order to bring down the lustre of Sirius to that of an equal star placed at such a 

 distance, I ought to reduce the aperture of my 20-feet telescope to less than the 

 2200th part of an inch; when certainly I could no longer expect to see any star 



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