doth not show it to advantage; and its spots are best seen when the feathers are spread as it flies.
The petrel is a bird not much unlike a swallow, but smaller, and with a shorter tail. It is all over black, except a white spot on the rump. They fly sweeping like swallows, and very near the water. They are not so often seen in fair weather; being foul-weather birds, as our seamen call them, and presaging a storm when they come about a ship; who for that reason don't love to see them. In a storm they will hover close under the ship's stern in the wake of the ship (as it is called) or the smoothness which the ship's passing has made on the sea; and there as they fly (gently then) they pat the water alternately with their feet as if they walked upon it; though still upon the wing. And from hence the seamen give them the name of petrels in allusion to St. Peter's walking upon the Lake of Gennesareth.
We also saw many bunches of seaweeds in the latitude of 39 32 and, by judgment near, the meridian of the island Tristan d'Acunha: and then we had about 2 degrees 20 minutes east variation: which was now again decreasing as we ran to the eastward, till near the meridian of Ascension; where we found little or no variation: but from thence, as we ran farther to the east, our variation increased westerly.
