[ 472 ] 
the eye. That as a confequence hereof, that part of the 
iky which is near the horizon, appears nearer to us than 
that part near the zenith. That the apparent nearnefs 
of the fky near the horizon, is always in a certain* 
though variable proportion, to the flate and proper- 
ties of the horizontal vapours. That as objects appear 
larger and nearer, when they are near the horizon, 
than when they are near the zenith, fo they appear 
larger through the medium of the atmofphere, than 
they would through a fpace devoid of air. That the 
alteration of the foci of optic glades, in order to adapt 
them for remote or near diflances, is chiefly de- 
pendant on the fame caufe, as that which produces 
the foregoing effects. That this caufe may be in- 
veiligated by proper experiments and confiderations- 
That herefrom, poflibly, the refinance of the aether 
beyond the regions of our atmofphere, and the pro- 
portional diflances of the fixed ftars, may be effayed 
at, with other matters of curiofity, import, and utir 
lity. 
24. The phenomena of nebulous and new ftars, 
have engaged the attention of curious aflronomers ; 
but none, that I know of, have given any reafons for 
the appearance of nebulous flars. Poflibly, what has 
been before, advanced, may alfo be applicable, for in- 
vefligating reafons for thofe ff range appearances in the 
remote parts of the univerfe. 
From many inflances, which might be produced, 
concerning the nature and properties of lights and il- 
luminations on the Earth’s furface, concerning the 
nature and properties of the Earth’s atmofphere, and 
concerning the atmolpheres and illuminations of co- 
mets, we may fafely conclude, that the atmofpheres 
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