I9o Mr. Bow ports Obfervations. 
there would be no-night atall ?* for the action of the fun. (if 
the fun fhould: be neceflary). would-be’ communicated to us, 
netwithftanding the interpofition of the earth. And would 
not the effect of that action, even at. noon when moft direc, 
be only to enlighten us, unattended with: heat,’ fo: effentially 
neceflary to enliven and invigorate the animal and vegetable 
world ?—-Would: not the elaític fluid, inftead of exhibiting a 
round luminous body, which we call the fun, be itfelf a con- 
tinued univerfal blaze of light ? And would not this, in the 
prefent conftitution of snes obftru& vifion, and. cepa al- 
ter the fcience of optics ? 
` The objections, implied in the foregoing queries, feem dedu- 
cible from the hypothefis. There are feveral which appear 
toarife from the comparifon of light with found. 
' 1* As found (or a vibrating, or undulating, motion in the air, 
which I confider here as fynoni ) is propagated from the fono- 
rous body in avdiredions ; and fei fishies: and is propagated be- 
yond or behind any obftacle in its way : fo light, if it was a vi: 
bration, or undulation, of the elaftic fluid, would furround, and 
be propagated behind an obftacle, like found: but this doeé 
not agree with the faét.—2° As found, or the vibrating mo- 
tion in the air, originating in a houfe or any other inclofuré; 
would, from a hole in one of the fides of it, be propagated ex 
ternally, in circles, of which the hole would be the centre ^: 
fo light, if it was a vibration, or occafioned by a vibration; of 
the elaftic fluid; after paffing through a hole, would be propa- 
gated in circles; of which the hole would be the centre.. But 
this -does - not. correfpond to the fact: for light, in = 
througt any SEEN pe always paffes in je lines. 
Befide 
