South latitude 30 degrees 47 minutes; east longitude 100 degrees 21 minutes 15 seconds.
Being a calm, I gave the men leave to bathe this afternoon, and was one of the first overboard myself.

Within an hour and a half after we had done bathing, a cry of a shark was raised, and in truth there was the monster (the first we had seen).

I mention this fact as tending to support what I have often heard stated, namely, that a shark's sense of smell is so keen that, if men ever bathe in seas where they are found, a shark is almost sure to appear directly afterwards.

This really occurred in the present instance.
We repeatedly caught many little animals which I believe are the VELELLA of Lamarck.

They consist of a flat oval cartilage, on which they float; there is a mouth in the inferior surface of this surrounded with many tentacula; on its superior surface is a crest which remains above water, and the wind blowing against it turns the animal round; they thus swim with a rotatory motion; the crest is placed obliquely to the length of the oval cartilage, and this position of it perhaps assists in producing the motion; the crest is perfectly transparent, but marked with little striae; the oval cartilage is marked with concentric striae, which indicate the lines of its growth; in some this cartilage is transparent, in others quite blue.
November 12.