Conjiruclion cf the Heavens^ i\ j 



after we fliall find rcafoii, from experience and obfervation, to 

 believe that there are parts of our {y{k&m: where the ftars are 

 not fcattered in the manner here fuppofed, we ought then to 

 make proper exceptions. 



But to return : if Ibme other high gage be fele6led from the 

 table, inch as 472 or 34^, the length of the vifual ray will be 

 found 461 and 415. And although, in confequence of what 

 has been faid, a certain degree of doubt may be left about the 

 arrangement and fcattering of the flats, yet when I recolle£l, 

 that in thofe parts of the milky way where thefe high gages 

 were taken, the flars were neither fo fmall, nor fo crowded, 

 as they mufl: have been on a fuppolirion of a much far- 

 ther continuance of them, wdien certainly a milky or ne- 

 bulous appearance muft have come on, 1 need not fear to have 

 over-rated the extent of my vifual ray. And indeed every 

 thins: that can be faid to fliorten it will onlv contnicl the limits 

 of our nebula, as it has in moft places been of fufficieut length 

 to go far beyond the bounds of it. Thus, in the fides of the 

 ftratum oppofite to our fituatlon in it, where the gages often 

 run below 5, our nebula cannot extend to 100 times the dif- 

 tance cf Sirius ; and the fame telefcopc, which could fhew 588 

 ftars in a field of view of 15 minutes, muft certainly have pre- 

 fented me alfo with the flars in thefe fituations as well as the 

 former, had the}^ been there. If we fhould anfwer this by ob- 

 ferving that they might be at too great a diftance to be per- 

 ceived, it will be allowing that there mufl at leafl be a vacancy 

 amounting to the length of a vifual ray not fhort of 400 tlmiCS 

 the dlflance of Sirius ; and this is amply fuflicient to make our 

 nebula a detached one. It is true, that it would not be con- 

 fiftent confidently to affirm that we were on an iOand unlefs 

 we had adually found ourfelves every where bounded by the 



ocean. 



