1768. It confifted of a fmall bladder about feven inches long, very
■ - • much refembling the air-bladder of fifties, from the bottom
Friday 7. Q£ ^jjich defcended a number of firings, of a bright blue-
and red, feme of them three or four feet in length, which
Upon being touched fling like a nettle, but with much
more force. On the top of the bladder is a membrane
which is ufed as a fail, and turned fo as to receive the wind
which way foever it blows: this membrane is marked in
fine pink coloured veins, and the animal is in every refpedt
an objedt exquifitely curious and beautiful.
We alfo took feveral of the fhell-fifhes, or teftaceous animals,
which are always found floating upon the water, particularly
the Helix Janthina and Violacea; they are about the
ftze of a fnail, and are fupported upon the furface of the
■ water by a fmall duller o f bubbles, which are filled with air
and eonfift of a tenacious flimy fubftanee that will not eafily
part with its contents; the animal is oviparous, and thefe
bubbles ferve alfo as a nidus for its eggs. It is probable that
it never goes down to the bottom, nor willingly approaches
any fhore; for the fhell is exceedingly brittle, and that of
few frefh water fnails is fo thin: every fhell contains about
a tea-fpoonful of liquor, which it eafily difcharges upon,
being touched, and which is of the moil beautiful red
purple that can be conceived. It dies linen cloth, and it
may perhaps be worth enquiry, as the fhell is certainly
found in the Mediterranean, whether it be not the Purpura o f
the ancients.
Saturday 8. On the 8th, in latitude 8° 25' North, longitude as0 4' Weft,,
we found a current fetting to the fouthward, which the next
day in latitude 70 58', longitude 33° 13' fhifted to the N. N.W.
i W. at the rate of one mile and a furlong an hour. The
variation here, by the mean of feveral azimuths, appeared to
be 8° 39' W.
On the 10th, Mr. Banks fhot the black-toed gull, not yet
defcribed according to Linnaeus’s fyftem; he gave it the name e—jv-—*
of Larus crepidatus: it is remarkable that the dung of this
bird is of a lively red, fomewhat like that of the liquor procured
from the fhells, only not fo 'fu ll; its principal food
therefore is probably the Helix juft mentioned. A current
to the N.W. prevailed more or lefs till Monday the 24th, Monday2-4.
when we were in latitude i° 7 N. and longitude 28° y©'.
On the 35th, we croffed the line with the ufual ceremonies Tutfday
in longitude 29? 30', when, by the refult of feveral very good-
azimuths, the variation was 20 24'.
On the 38th, at noon, being in: the latitude o f Ferdinand Friday 28.
Horonha, and, by the mean of feveral obfervations by Mr.
Green and my felf, in longitude 320 rt 16" W. which is to the
weftward of it by fome charts, and to the caftward by others*
we expedited to fee the ifland, or fome of the fhoals that are
laid down in the charts between it and the main, but w e
few neither one nor the other.-
In the evening of the 39th, we obferved that luminous Saturday^:
appearance of the fea which has been fo often mentioned by
navigators,, and of which fuch various eaufes have been--
affigned ; fome fuppofing.it to be occafioned by filh, which’
agitated the water by darting at their prey, fome by the pu-
erefadtion of fifli and other marine animals-,, fome by electricity,
and others referring it into a great variety of different
eaufes.. It appeared to emit flafhes of light exadtly-
refembling thofe of lightning, only not fo confiderable, but
they were fo frequent that fometimes eight or ten were'
vifible almofl at the fame moment. We were of opinion:
that they proceeded from fome luminous animal, and upon:
throwing out the calling net our opinion was confirmed : it;
brought up a fpecies of the Medufa, which when it. came on>
board: