[92] Proceedings of the Royal Geographical Society, vol. xv.
[93] Phil. Mag., February, 1870.
[94] Brit. Assoc. Report, 1869, Sections, p. 160.
[95] Journal of Royal United-Service Institute, vol. xv.
[96] Dr. Carpenter (Proc. of Roy. Geog. Soc., vol. xviii., p. 334) misapprehends me in supposing that I attribute the Gibraltar current wholly to the Gulf-stream. In the very page from which he derives or could derive his opinion as to my views on the subject (Phil. Mag. for March, 1874, p. 182), I distinctly state that “the excess of evaporation over that of precipitation within the Mediterranean area would of itself produce a considerable current through the Strait.” That the Gibraltar current is due to two causes, (1) the pressure of the Gulf-stream, and (2) excess of evaporation over precipitation in the Mediterranean, has always appeared to me so perfectly obvious, that I never held nor could have held any other opinion on the subject.
[97] Paper read to the Edinburgh Botanical Society on January 8, 1874.
[98] Proc. Roy. Geog. Soc., vol. xviii., p. 362. A more advantageous section might have been chosen, but this will suffice. The section referred to is shown in [Plate III.] The peculiarity of this section, as will be observed, is the thinness of the warm strata at the equator, as compared with that of the heated water in the North Atlantic.
[99] The temperature of column C in Dr. Carpenter’s section is somewhat less than that given in the foregoing table; so that, according to that section, the difference of level between column C and columns A and B would be greater than my estimate.
[100] Captain Nares’s Report, July 30, 1874.
[101] See [Chapter IV.]