The Castlereagh, originally purchased in Sydney, being reported to be quite unfit for surveying purposes, was sold to her former owner; and the Bramble was recommissioned as tender to the Rattlesnake, and continued under the command of Lieutenant Yule.

Ten additional men were entered on board, increasing our complement to 190 officers and men, of whom 36 were placed on board the schooner.

After a thorough refit, both vessels were at length quite ready for sea.
SURVEY ENTRANCE OF PORT JACKSON.
Meanwhile a minute survey was made by Lieutenants Dayman and Simpson of the inner entrance to Port Jackson, where a reef, called the Sow and Pigs (distinguished by a beacon and a light vessel) in the middle of the passage, leaves only a narrow available channel on either side.

The exact boundaries of them, with the depth of water, were to be determined, especially to ascertain whether a line-of-battle ship, with her full armament, could pass into the harbour.

The shoalest part of the west channel was found to have 21 feet, and of the east 24 feet at low-water (the rise and fall of tide being from 5 to 8 feet); consequently, at high-water there would be room for a three-decker to enter.* This work was in connection with a proposed dry dock** on Cockatoo Island, above Sydney, towards the expenses of which the Imperial Government were willing to contribute, provided it were made of such a size as to be available for large steamers and line-of-battle ships.
(*Footnote.