The first two parts of this paper—Physical Geography and Salinity—were communicated to the Society on May 18th, 1891, and published in the Transactions, Vol. XXXVI, Part III., No. 23, pp. 641–729.

Various circumstances have prevented me from sooner presenting the concluding part of the discussion. I postponed publication again and again, in the hope that it might be possible to discuss the results more thoroughly, and deduce from them more clearly than I have been able to do the laws which regulate the heat-transactions of sea-water of varying salinity, contained in basins of differing degrees of isolation from the circulation of the ocean. At length the conclusion has been arrived at that the observations are not sufficiently uniform, regular, and close to warrant the expenditure of the time devoted to their discussion. Many months of work have been occupied in proving that some special manner of classifying and treating the data led to no definite result. Thus, it is unnecessary to describe several series of voluminous calculations, or to bring forward a great number of maps and sections on which the distribution of temperature was plotted in different ways. It is difficult to establish theoretical conclusions of a general and far-reaching kind from my work, and I have not attempted to compare it with the many memoirs published in continental journals, on the temperature of lakes, fjords, and enclosed seas.