2c^S Mr. Herschel on iht 



ftraggling ftars of coiirfe will be very few in number ; ancl^ 

 therefore the giound of the heavens will aflume that purity 

 which 1 have always obferved to take place in thofe regions. 



Enumeration of very compowid Nebula or Milky^Ways, 



As we are ufed to call the appearance of the heavens, whers- 

 it is furrounded Vv'ith a bright zone, the Milky-V/ay, it may 

 not be amifs to point out fome other very remarkable Nebulas- 

 which cannot well be lefs, but are probably much larger thaiv 

 our own fyftem ; and, being alfo extended, the inhabitants oF 

 the planets tliat attend the ftars which compofe them muft 

 likewife perceive the fame phenomena. For which reafon they 

 may alfo be called milky-ways by way of difiindlion. 



My opinion of their fize is grounded on the following ob- 

 fervations. There are many round nebulae, of the firil: form,. 

 of about five or fix minutes in diameter, the flars of which I^ 

 can lee very diftindlly ; and on comparing them with the vifual 

 yay calculated from fome of my long gages, I fuppofe, by the ap- 

 pearanceof the fmall ftars in thofe gages, that the centers of thefe 

 round nebulae may be 600 times the diflance of Sirius from us. 



In eftimatins; the diflance of luch cluflers I confulted- 

 rather the comparatively apparent fize of the fl-ars than 

 their mutual diftance; for the condenfation in thefe cluifers- 

 being probably much greater than in our own fyftem, if we 

 "were to overlook this circumfi:auce and calculate b}^ their appa- 

 rent compreffion, where, in about fix minutes diameter, there 

 are perhaps ten or more ftars in the line of meafures, we fhould 

 find, that on the fuppofition of an equal fcattering of the flars- 

 throughout all nebulae, the diflance of the center of fuch a 

 clufter from us could not be lefs than 6000 times the diflance 



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