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clouds near the horizon, with a lively gold-yellow or orange j it is,,
therefore, by no means extraordinary to fee, at fun-letting, a
greenilh Iky ortcloud, and it may be. obferved frequently in Europe,.
But, as the.rifing and fetting fun caufes, between and. about t&e-.
tropics, the tinifts of the Iky and clouds to be infinitely brighter
than any where elfe, it. happens now.and then,, that: all. the appearances
o f the Iky and clouds, are more Uniting, and brilliant, and
therefore more noticed. I. had art opportunity to obferve, in the.
year 1774,. April 2d, in 9° 30' South latitude, at- fun-fetting, a.
beautiful green cloud; fome others at a. greater defiance were o f an.
olive-colour, and even part o f the Iky was tinged.with, a lively,, delicate
green..
. Secondly,. Th.e refradtion o f light through clouds and rains,, caufes
a Rainbow oppofite to the fun j a phenomenon which,, however
beautiful and ftriking,, is fo common, and the manner o f its formation
fo well known, that it hardly requires here any particular
notice : but I cannot pafs by in filence, that whilft we. were going,,
in 1773, from New Zeeland, the firfl time, to O-Taheitee, I had:
an opportunity o f obferving, from June 7th to July 1.2th, every,
morning conftantly, a rainbow, or part of a rainbow,, on the horizon.
Though this remark is but trivial, it proves, however, that
we had almoft daily fmall Ihowers of rain, and that we paid particular
attention to every objedt which deferved obfervation..
T h e
The fainter, ligh t o f the moon caufes likewife rainbows, but they'
are lefs noticed on account o f their faint and weak .colours ; I obferved
one with remarkably bright colours on June 29th, 17 73, another
on July. 6th, the fame year,, and another on March 19th, .177.5,.
when near the Cape o f Good.Hope- Ariftótle i s , I. believe, the.'firft-
who .obferved. this- phænomenon-
Thirdly,,- when.theiair is: charged with dénie vapours;., and'.often:
when they are frozen into fnow or fleet,, there appears a Halo about
the fun or moon, which is by no means remarkable upon the
whole;, but it has been obferved that: Halos, precede high winds,
fqualls and often rain and fnow.. Though I had.frequent,opportunities
to fee this: obfervation confirmed, L did not. however, always.
minute it down in my journal ; I find only the following memorandums..
On February 2 5 th , X'774, we law, a large Halo about, the
moon, and that very night came on fqualls with rain, and the next
morning we, had thé fame: weather, with loud thunder, claps.. Ois
January. 5 th , A . . M - r.775, a large Halo,, occupying: more thaï»
44° o f the heavens, was, feen. about, the fun, dark, in the: middle,
feright and whitifh with, fome colours of the rainbow. In. the circle,
and, we had rain, and now and then fqualls. .
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