and the greater proportion of it will come in between Break-sea Spit and the reefs, and be late in reaching the remoter parts; and if we suppose the reefs to terminate to the north, or north-west of the Sound, or that a large opening in them there exist, another flood tide will come from the northward, and meet the former; and the accumulation of water from this meeting, will cause an extraordinary rise in Broad Sound and the neighbouring bays, in the same manner as the meeting of the tides in the English and Irish Channels causes a great rise upon the north coast of France and the west coast of England.

That an opening exists in the reefs will hereafter appear; and captain Cook’s observations prove, that for more than a degree to the north-west of Broad Sound, the flood came from the northward.  I found, when at anchor off Keppel Bay, and again off Island Head, that the flood there came from the east or south-east; but when lying three miles out from Pier Head, there was no set whatever; and I am disposed to think that it is at the entrance of Broad Sound, where the two floods meet each other.

CHAPTER IV.

The Percy Isles:  anchorage at No. 2. 
Boat excursions. 
Remarks on the Percy Isles; with nautical observations. 
Coral reefs:  courses amongst them during eleven days search for a passage through, to sea. 
Description of a reef. 
Anchorage at an eastern Cumberland Isle. 
The Lady Nelson sent back to Port Jackson. 
Continuation of coral reefs;
and courses amongst them during three other days. 
Cape Gloucester. 
An opening discovered, and the reefs quitted. 
General remarks on the Great Barrier;
with some instruction relative to the opening.

[EAST COAST. PERCY ISLES.]

TUESDAY 28 SEPTEMBER 1802

On quitting Broad Sound, we steered for the north-easternmost of the Northumberland Islands., which I intended to visit in the way to Torres’ Strait.  These are no otherwise marked by captain Cook, than as a single piece of land seen indistinctly, of three leagues in extent; but I had already descried from Mount Westall and Pier Head a cluster of islands, forming a distinct portion of this archipelago; and in honour of the noble house to which Northumberland gives the title of duke, I named them Percy Isles.

(Atlas, Plate XI.)

At noon, the observed latitude on both sides was 21 deg. 51’ 20”; the west end of the largest North-point Isle bore S. 18 deg.  W. three or four leagues, and the Percy Isles were coming in sight ahead.  The weather was hazy; and the wind at E. S. E. preventing us from fetching No. 2, the largest isle, we tacked at five o’clock, when it bore S. 31 deg. to 54 deg.  E, two or three leagues; No. 5, the north-westernmost of the cluster, bearing N. 24 deg.  W., two miles and a half.  At dusk the anchor was dropped in 14 fathoms, sandy ground, two or three miles from some rocky islets which lie off the west side of No. 2.  The flood tide at this anchorage came from the north-east, one mile per hour.