On the next day, Saturday the 24th, we came into the north-east trade wind, and on Friday the 30th saw Bona Vista, one of the Cape de Verd islands; we ranged the east side of it, at the distance of three or four miles from the shore, till we were obliged to haul off to avoid a ledge of rocks which stretch out S. W. by W. from the body, or S. E. point of the island, to the extent of a league and a half. Bona Vista, by our observation, lies in latitude 16 N. and longitude 21° 5ʹ West.
On the 1st of October, in latitude 14° 6ʹ N. and longitude 22° 10ʹ W. we found the variation by a very good azimuth to be 10° 37ʹ W. and the next morning it appeared to be 10°. This day we found the ship five miles a head of the log, and the next day seven. On the third, hoisted out the boat to discover whether there was a current, and found one to the eastward, at the rate of three quarters of a mile an hour.
During our course from Teneriffe to Bona Vista we saw great numbers of flying fish, which from the cabin windows appear beautiful beyond imagination, their sides having the colour and brightness of burnished silver; when they are seen from the deck they do not appear to so much advantage, because their backs are of a dark colour. We also took a shark, which proved to be the _Squalus Carcharias_ of Linnæus.
Having lost the trade wind on the 3d, in latitude 12° 14ʹ, and longitude 22° 10ʹ, the wind became somewhat variable, and we had light airs and calms by turns.
On the 7th, Mr. Banks went out in the boat and took what the seamen call a Portuguese man of war; it is the _Holuthuria Physalis_ of Linnæus, and a species of the _Mollusca_. It consisted of a small bladder about seven inches long, very much resembling the air-bladder of fishes, from the bottom of which descended a number of strings, of a bright blue and red, some of them three or four feet in length, which, upon being touched, sting like a nettle, but with much more force. On the top of the bladder is a membrane which is used as a sail, and turned so as to receive the wind which way soever it blows: this membrane is marked in fine pink-coloured veins, and the animal is in every respect an object exquisitely curious and beautiful.