of ?iew Nebulae and Clujlers of Stars . 223 
If thefe clufters and nebulae were all of the fame ftiape, and 
had the fame gradual condensation, we fhould make but little 
progrefs in this inquiry; but, as we find fo great a variety in 
their appearances, we (hall be much fooner at a lofs how to 
account for fuch various phenomena, than be in want of ma- 
terials upon which to exercife our inquifitive endeavours. 
Some of thefe round clufters confift of ftars of a certain 
magnitude, and given degree of compreflion, while the whole 
clufter itfelf takes up a fpace of perhaps- 10 minutes;- others 
appear to be made up of ftars that are much fmaller, and 
much more compreffed, when at the fame time the clufter 1 
itfelf fubtends a much fmaller angle, fuch as yminutes. This 
diminution of the apparent fize, and- compreflion of ftars, as 
well as diameter of the clufter to 4, 3, 2 minutes, may very 
confiftently be afcribed to the different diftances of thefe clu- 
fters from the place in which we obferve them ; in all which 
cafes we may admit a general equality of- the fizes, and com- 
preflion of the ftars that compofe them, to take place. It is 
alfo highly probable that a continuation of fuch decreafing 
magnitudes, and enereafing compreflion', will juftly account 
for the appearance of round, eafily refolvable, nebulae ; where 
there is- almoft a certainty of their being' clufters of ftars. 
And no Aftronomer can hefitate to go ftill farther, and extend 
his furmifes by imperceptible fteps to other nebulas, that ftill* 
preferve the fame charafteriftics, with the only variations of 
vaniftiing brightnefs, and reduction of fize. 
Other clufters there are that, when they come to be com- 
pared with fome of the former, feem to contain ftars of air 
equal magnitude, while their compreflion appears to be confi- 
derably different. Here the fuppofition of their being at dif- 
ferent diftances will either not explain the apparently greater 
JLi 1 2 
com^“ 
