The very general toleration of foreign religions, the regard paid to the means of education, the freedom of the press, the facilities offered to all foreigners, and especially, as I am bound to add, to every one professing the humblest pretensions to science, should be recollected with gratitude by those who have visited Spanish South America.
DECEMBER 6, 1833.
The "Beagle" sailed from the Rio Plata, never again to enter its muddy stream.

Our course was directed to Port Desire, on the coast of Patagonia.

Before proceeding any farther, I will here put together a few observations made at sea.
Several times when the ship has been some miles off the mouth of the Plata, and at other times when off the shores of Northern Patagonia, we have been surrounded by insects.

One evening, when we were about ten miles from the Bay of San Blas, vast numbers of butterflies, in bands or flocks of countless myriads, extended as far as the eye could range.

Even by the aid of a telescope it was not possible to see a space free from butterflies.