jtjS Mr. Herschel on the 



ftragglmg ftars of courle will be very few in number ; and 

 therefore the ground of the heavens will afllime that purity 

 "which 1 have always oblerved to take place in thofe regions. 



Knvmeration of *very compcund Nebulise or Milky'Ways, 



As we are ufed to call the appearance of the heavens, wherd 

 it is furrounded with a bright zone, the Milky-Way, it may 

 not be amifs to point out fome other very remarkable Nebnlae 

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

 •our own fyflem ; and, being alfo extended, the inhabitants of 

 the planets that attend the fears which compofe them muft 

 likewife perceive the fame phaenomena. For which reafon they 

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



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

 fervations. There are'^many round nebula, of the firft form, 

 of about five or fix minutes in diameter, the ftars of which t 

 can iee vej;y difl;infl:ly ; and on comparing them with the vifual 

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

 pearance of the fmall ftars in thofe gages, that the centers of thefej 

 round nebulae m.ay be 600 times the diftance of Sirius from us. 



In eflimating the diftance of fuch cluflers I confulted- 

 rather the comparatively apparent fize of the ftars than' 

 their mutual diflance; for the condenfation in thelb cluflers.' 

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

 were to overlook this circumllance and calculate by their appa- 

 rent comprefiicn, where, in about fix minutes diamefef, there 

 are perhaps ten or more f^ars in the line of irieafures, we fhould 

 find, that on the fuppofition of an equal fcattering of the flars.' 

 throughout all nebula, the difi:ance of the center of fuch a 

 clufler from us could not be lefs than 6000 times the dillance^ 



