the main, and the steamer got finally clear, and stood down the river to rejoin the Westfield and the Clifton. On coming alongside, Mr. Oltmanns was at once transferred, by the kind suggestion of Captain Baldwin, to the Clifton, and being made as comfortable as circumstances admitted, was put under care of Dr. Nestell, the surgeon of the boat. The warm-hearted commander of that vessel will always retain the sincere gratitude of every member of the Coast Survey party for his endeavors in behalf of their brave associate. The doctor probed the wound of Mr. Oltmanns, but was unable to discover the ball, which, by the by, was extracted six months later, by Dr. Lieberman, in Washington City, after it had gradually moved from the breast to the right shoulder blade. Dr. Nestell had no great hopes at the time he took charge of the wounded officer, but thought that with proper care and attention, it might be possible for him to recover. At eight o'clock P. M. the vessels anchored in Lake Borgne, and the next morning, the 16th of May, the whole expedition returned to Ship Island. Captain (now Admiral) Porter visited Mr. Oltmanns, and made suitable arrangements at once for his removal to his friends in New York in the spacious and comfortable steamer Baltic, Captain Comstock. Between the 16th and 22d of May, the boilers of the Sachem were cleaned, and some repairs made in her machinery, at the end of which time Mr. Gerdes was directed by the commander to repair to the Southwest Pass of the Mississippi, and there to replace the missing buoys and stakes, and to survey the entrance. Leaving Ship Island on the 22d of May, the Sachem entered the Pass a l'Outre mouth of the Mississippi, and reached Fort Jackson on the 23d in the evening. Here the can buoys and five or six anchors and chains which had been removed by the confederates were found, and brought down and replaced by the Sachem in their original locations at the Southwest Pass. This important inlet of the Mississippi, at present the most accessible and best, was surveyed, a manuscript chart was made by the officers of the Coast Survey, and copies of the same were sent at once to Flag-officer Farragut, Captain Porter, Major-General Butler, and to the Coast Survey office in Washington; at the latter place the chart was lithographed immediately, and extensively distributed in New York and New Orleans.