17th August.  Shoals of tunny-fish, (fish four and five feet long, and belonging to the dolphin tribe,) were seen tumbling about the ship.  A harpoon was quickly procured, and one of the sailors sent out with it on the bowsprit; but whether he had bad luck, or was unskilled in the art of harpooning, he missed his mark.  The most wonderful part of the story, though, was that all the fish disappeared as if by magic, and did not appear again for some days; it seemed as if they had whispered and warned each other of the threatened danger.

All the oftener, however, did we see another inhabitant of the sea, namely, that beautiful mollusca, the physolida, called by the sailors Portugiesisches Segel-schiff; (Portuguese sailing-ship.) When floating upon the surface of the sea, with its long crest, which it can elevate or depress at pleasure, it really resembles a delicate tiny little sailing vessel.  I was very desirous of catching one of these little creatures, but this could only be effected by means of a net, which I had not got, nor had I either needle or twine to make one.  Necessity, however, is the mother of invention; so I manufactured a knitting needle of wood, unravelled some thick string, and in a few hours possessed a net.  Very soon afterwards a mollusca had been captured, and placed in a tub filled with sea water.  The little creature’s body is about six inches long and two inches high; the crest extends over the whole of the back, and in the middle, where it is highest, measures about an inch and a half.  Both the crest and body are transparent, and appear as if tinged with rose colour; from the belly, which is violet, are suspended a number of threads or arms of the same colour.

I hung the little thing up to dry at the stern, outside the ship; some of the threads reached down into the water (a depth of at least twelve feet), but most of them fell off.  After the animal was dead, the crest remained erect, and the body perfectly filled out, but the beautiful rose colour gradually changed to white.

18th August.  Today we had a heavy thunder-storm, for which we were very grateful, as it cooled the air considerably.  Between 1 and 2 degrees, or 3 degrees North latitude, frequent changes in the weather are very common.  For instance, on the morning of the 20th we were overtaken by a strong wind, which lashed up the sea to a great height, and continued until evening, when it gave way to a tropical shower, which we at home should call a perfect water-spout.  The deck was instantaneously transformed into a lake, while at the same time the wind had so completely fallen that even the rudder enjoyed a holiday.

This rain cost me a night’s rest, for when I went to take possession of my berth, I found the bed-clothes drenched through and through, and was fain to content myself with a wooden bench for a couch.

On the 27th of August we got beyond these hostile latitudes, and were received by the anxiously desired south-east trade wind, which hurried us quickly on our voyage.