To the northward of Cape Diamond is the bay of Sirahama, which is quite deep, and as it has also several sand-beaches, it may be mistaken for Simoda; but as you approach this bay, Cape Diamond will shut in the Ukona rocks, and Rock island to the southward; while in the Simoda roads they are visible from all points. Cape Idzu, latitude 34° 36′ 03″ N. ” ” longitude 138° 52′ 32″ E. Rock Island, latitude 34° 34′ 20″ N. ” ” longitude 138° 57′ 10″ E. S. W. ½  W. from Kozu-Sima, distant about 20 miles, and south, a little westerly, from Cape Idzu, distant about 40 miles, there are two patches of dangerous rocks, 15 or 20 feet high, which have been named Redfield rocks. They are in—Latitude 33° 56′ 13″ N., Longitude 138° 48′ 31″ E.; and Latitude 33° 57′ 31″ N., Longitude 138° 49′ 13″ E. These positions may not be strictly correct, but it is believed they are not much out of the way. Several errors in the first edition of these directions, published in July last, have been corrected in the above.—W. L. M. SAILING DIRECTIONS FOR YEDO. BY LIEUT. WM. L. MAURY, U. S. N. Vessels from the southward, bound to this bay, should pass up to the westward of the chain of islands lying off the gulf of Yedo, and are cautioned against mistaking the deep bight of Kawatsu bay for the entrance of Uraga channel, for on the northeast side of this bay there is a ledge of rocks several miles from the shore, bearing from Cape Sagami about W. N. W., distant ten miles, upon which one of the vessels of our squadron grounded. A stranger without a correct chart would naturally make this mistake, as the opening of the channel is not seen at a distance from this quarter, the shore appearing as an unbroken line. The entrance to the channel bears from the centre of Oho-Sima N. E. by N., distant about twenty miles. Stand in upon this line, and the Saddle hill to the northward of Cape Sagami will be readily recognised, as well as the round black knob on the eastern side of the channel. On approaching Uraga, the Plymouth rocks will be plainly seen; give these a berth of half a mile to clear the Ingersoll Patch, a sunken rock with but one fathom on it, and which is the only known danger in the channel. Between Plymouth rocks and Cape Kami-Saki, the ground is clear and the anchorage good, if care be taken to get pretty well in, so as to avoid the strong tides which sweep round the latter with great rapidity. A spit makes out a short distance to the southward of Kami-Saki; but to the northward of the cape, the shore is bold, and the water very deep.