Observations on the temperature of the ocean and atmosphere, and on the density of sea-water, made during a voyage to Ceylon. In a letter to Sir Humphry Davy, LL. D. F. R. S. By John Davy, F. R. S

Abstract The experiments on the specific gravity of sea-water, detailed in this paper, were partly conducted at sea, and partly after the author’s arrival at Ceylon; and the results lead him to adopt the opinion that the ocean resembles the atmosphere in being, cæteris paribus, nearly of the same specific gravity throughout. The water used in the ex­periment was always taken from the surface of the ocean. The vari­ation of specific gravity was most observable when the water was rough and agitated, and seemed in one instance diminished by heavy rain. Dr. Davy doubts whether a modern traveller of high authority is correct in supposing that a peculiar specific gravity belongs to the water of each zone; for in his own experiments, the water taken in latitude 0° 12' S., and 22° 36' S., was of similar specific gravity, as also that taken at 34° 25' S., and that washing the shores of Columbo.