This passenger--the first and only one we had had, except to go from port to port, on the coast, was no one else than a gentleman whom I had known in my better days; and the last person I should have expected to have seen on the coast of California--Professor N----, of Cambridge. I had left him quietly seated in the chair of Botany and Ornithology, in Harvard University; and the next I saw of him, was strolling about San Diego beach, in a sailor's pea-jacket, with a wide straw hat, and barefooted, with his trowsers roiled up to his knees, picking up stones and shells. He had travelled overland to the North-west Coast, and come down in a small vessel to Monterey. There he learned that there was a ship at the leeward, about to sail for Boston; and, taking passage in the Pilgrim, which was then at Monterey, he came slowly down, visiting the intermediate ports, and examining the trees, plants, earths, birds, etc., and joined us at San Diego shortly before we sailed. The second mate of the Pilgrim told me that they had an old gentleman on board who knew me, and came from the college that I had been in. He could not recollect his name, but said he was a "sort of an oldish man," with white hair, and spent all his time in the bush, and along the beach, picking up flowers and shells, and such truck, and had a dozen boxes and barrels, full of them. I thought over everybody who would be likely to be there, but could fix upon no one; when, the next day, just as we were about to shove off from the beach, he came down to the boat, in the rig I have described, with his shoes in his hand, and his pockets full of specimens. I knew him at once, though I should not have been more surprised to have seen the Old South steeple shoot up from the hide-house. He probably had no less difficulty in recognizing me. As we left home about the same time, we had nothing to tell one another; and, owing to our different situations on board, I saw but little of him on the passage home. Sometimes, when I was at the wheel of a calm night, and the steering required no attention, and the officer of the watch was forward, he would come aft and hold a short yarn with me; but this was against the rules of the ship, as is, in fact, all intercourse between passengers and the crew. I was often amused to see the sailors puzzled to know what to make of him, and to hear their conjectures about him and his business. They were as much puzzled as our old sailmaker was with the captain's instruments in the cabin.