An understanding of the oceanography of the Celtic Sea requires anunder-standing of the exchanges of water around four headlands, Ushant, Lands End, St Davids Head and Carnsore Point. As a sequel to the study on the flow past Ushant already presented (Cooper, 1960b), this paper and the following one by Cooper, Lawford & Veley are attempts to achieve a better understanding of the exchanges around Lands End andin the neighbourhood of the Scilly Isles (Fig. 1).

Matthews (1914, p. 20) said: 'The charts published in this report show that the saltest water enters the Irish area between Lands End and the Scilly Islands, and detailed observations made along this line on several cruises at intervals of from half a mile to one mile onthe Marine Biological Association's steamers have shown that the axis of highest salinity lies midway between the Longships Rock and the Seven Stones Lightship, that is, at a distance of only a few miles off Lands End. This current of salt warm water is derived from a current which has already entered the English Channel from a southwesterly direction, and has in part turned northwards and north-westwards to escape into the Irish Channel. It is practically certain that this water has come from the mouth of the English Channel and not directly from the open sea because further westwards a great area of lower surface salinity stretches southwards across the fairway and prevents any such direct current.' Harvey (1925, fig. 19) accepted Matthews' interpretation and later (1929) from a study of geopotential topographies deduced that a residual current ran between Lands End and the Scillies in June 1924 in a N.N.E. applies more nearly in the passage itself..