Since 1921 hydrographic data have been collected by the S.S. Salpa and several merchant vessels, the records being published in the Rapport Atlantique and the Bulletin Hydrographique each year. A description of the conditions in the mouth of the Channel—the varying temperature, salinity, and movements of the water masses—during the years 1925–1928 was published in this Journal, Vol. XVI., pp. 791–820, and included a review of the objects of these investigations and the methods used in working up the collected data. This present publication forms a continuation of this. The same methods of dealing with the data have been used.