188 Mr. Bowpotn’s Odfrvattons 
__At is offered in full confidence, that our celebrated country- - 
“man, whofe happy genius has contributed fo largely to the ad- 
vancement of philofophic knowledge, will be pleafed with any 
attempt for that purpofe, whether iuccefsful or not, even though 
it fhould be upon peers that = not ——— harmonize 
with fome of his owr.. 
^ "The Doctor, diflatisfied with the received doctrine concern- 
ing light, offers feveral objections to it in the form of feces 
and in the fame form propofes an ——' of hist own: both 
of which will be confidered. — 
- With refpe& to the hypothefis, it is-afked— * « May not 
all the phenomena of light be more conveniently folved, by 
fuppofing univerfal {pace filled witlra fubtle elaftic fluid, which, 
when at reft, is not vifible, but whofe vibrations affect that 
fine fenfe in the eye, as thofe of air do the groffer organs of 
the ear ? We do not, in the cafe of found, imagine that any 
fonorous particles are thrown off from a bell, for inftance, and 
fly in ftraight lines. to the car : why muft we believe that lu- 
minous particles leave the fun, and proceed tothe eye ? Some 
diamonds, if rubbed, fhine in the dark, without lofing any 
part of their matter. I can make an electrical {park as big as 
the flame of a candle, much brighter, and therefore vifible fur- 
ther ; yet this is without fuel :*and I am perfuaded no part of 
the electric fluid flies off in fuch cafe to diftant places, but all 
goes directly, and is to be found in the place to which I deftine 
—May not different degrees of the vibration of the above- 
e nti ned uniyerfal medium, occafion the appearances of dif- 
it Cc cus? sh z think. the ele&ric fluid is always the fame 
e 
^49. See Letters and eae on n Philofophical Subjeds. P. e edit, 1769. 
