At day-break I was very much distressed and astonished to see one of the men on a sudden start up under the influence of delirium, and attempt to throw himself into the water, from which the combined strength of three or four of the crew with difficulty restrained him. He was one of the best men I had with me; his sudden and serious illness had doubtless been produced by the draughts of saltwater which he had swallowed during the night. He had been accustomed to indulge in very liberal potations while we were up the river, and now, when from necessity the allowance was restricted to a gallon per day, he had most foolishly attempted in the dark to quench his thirst with the salt waters of the advancing tide. In the afternoon we rejoined the ship, and he was placed under the care of Mr. Bynoe; but it was some time before he fully recovered from the effects of his rash experiment. The day was very oppressive, the thermometer being 105 degrees in the shade, and there was no wind. We were cordially greeted by our shipmates upon our return, and both Mr. Forsyth and myself enjoyed the luxury of a night's rest in our hammocks; a most agreeable change after the hot stones upon which we had generally been compelled to court repose during our exploration. We had both suffered much inconvenience from the attacks of flies upon our visual organs, necessarily exposed and undefended as they had been when we were occupied during the observations and in viewing the strange scenes of the last eighteen days. The irritation upon the lids produced a copious discharge, which fairly sealed them up at night; so that, at last, in order to have them ready for immediate use, I found it requisite to sleep with a wet linen cloth covering each eye. We heard with great satisfaction that Lieutenant Emery's search for water had been completely successful, and that two large wells had been dug in the valley, abreast of which the ship was anchored. During our absence the barometer had ranged between 30.08 and 29.97; the minimum height being always at noon. There had been several sharp squalls from the eastward, beginning at south-east and ending at north-east, with a few showers of rain. North-west, or seabreezes, were regular near the changes of the moon, and of greater duration. No meteors were observed since the 16th, but between the 7th and 11th they were very numerous. GEOLOGICAL SPECIMENS. November 20.