VOL. LXXIX.] PHILOSOPHICAL TRANSACTIONS. 585^ 



light diminishes as the squares of the distances increase, and that in every re- 

 flection a very considerable part is entirely lost, the motion of comets, by which 

 the space through which they run is measured out to us, while on their return 

 from the sun we see them gradually disappear as they advance towards their 

 aphelia, would be sufficient to convince us that bodies shining only with bor- 

 rowed light can never be seen at any very great distance. This consideration 

 brings us back to the sun, as a refulgent fountain of light, while it establishes 

 at the same time beyond a doubt that every star must likewise be a sun, shining 

 by its own native brightness. Here then we come to the more capital parts of 

 the great construction. 



These suns, every one of which is probably of as much consequence to a 

 system of planets, satellites, and comets, as our own sun, are now to be con- 

 sidered, in their turn, as the minute parts of a proportionally greater whole. 

 I need not repeat that by my analysis it appears, that the heavens consist of 

 regions where suns are gathered into separate systems, and that the catalogues I 

 have given comprehend a list of such systems ; but may we not hope that our 

 knowledge will not stop short at the bare enumeration of phenomena capable of 

 giving us so much instruction ? Why should we be less inquisitive than the 

 natural philosopher, who sometimes, even from an inconsiderable number of 

 specimens of a plant, or an animal, is enabled to present us with the history of 

 its rise, progress, and decay ? Let us then compare together, and class some 

 of these numerous sidereal groups, that we may trace the operations of natural 

 causes as far as we can perceive their agency. The most simple form, in which 

 we can view a sidereal system, is that of being globular. This also, very fa- 

 vourably to our design, is that which has presented itself most frequently, and 

 of which I have given the greatest collection. 



But first of all it will be necessary to explain what is our idea of a cluster of 

 stars, and by what means we have obtained it. For an instance, I shall take the 

 phenomenon which presents itself in many clusters : it is that of a number of 

 lucid spots, of equal lustre, scattered over a circular space, in such a manner as 

 to appear gradually more compressed towards the middle ; and which compres- 

 sion, in the clusters to which I allude, is generally carried so far as, by imper- 

 ceptible degrees, to end in a luminous centre, of a resolvable blaze of light. 

 To solve this appearance, it may be conjectured that stars of any given, very 

 unequal magnitudes, may easily be so arranged, in scattered, much extended, 

 irregular rows, as to produce the above described picture ; or, that stars, scat- 

 tered about almost promiscuously within the frustrum of a given cone, may be 

 assigned of such properly diversified magnitudes as also to form the same pic- 

 ture. But who, that is acquainted with the doctrine of chances, can seriously 

 maintain such improbable conjectures ? To consider this only in a very coarse 



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