* Lat. 32° N.

note * page 81 Murray, , “Structure and Origin of Coral Reefs,” Proc. Roy. Soc. Edin., vol. x. p. 508, 1880.Google Scholar

note * page 85 See Appendix, Table III.

† See Irvine, and Voodhead, , Froc. Moy. Soe. Edin., vol. xv. p. 308, 1888.Google Scholar

note * page 88 Theoretically, urea plus two molecules of water give carbonate of ammonia. If, therefore, carbonate of ammonia be a stage in the formation of urea, it is not unnatural to suppose that, in shell-forming animals, the shell formation may be the stage without any formation of urea. For special method for the determination of saline ammonia in sea water, see page 101, Appendix.

note * page 89 These samples were received through Captain Wharton, F.R.S., Hydrographer to the Admiralty.

note * page 90 The sulphate of ammonia is in turn absorbed by the marine flora which forms the food of the marine fauna, and is in part resolved into nitrates and free nitrogen.

note †page 90 Bischof, Chem. and Phys. Geol., vol. i. p. 180, says:—”In order to form a conception of what testacea are capable of effecting by organic agency, I determined the weight of ten oysters and their shells. After they had been opened the enclosed sea water was, as far as possible, removed. The weight of the shells varied from 278 to 7'57 that of the oysters..… “No one can doubt that it was the carbonate of lime dissolved in the sea water which alone furnished the material for the formation of these shells. “If now we assume that the sea water contains of carbonate of lime, and that the oysters are capable of deriving all their calcareous substance from the water by organic agency, it follows that the above number of oysters required for the formation of their shells 345 to 587 lbs., or 5 “2 to 8 “9 cubic feet of sea water. “This quantity is from 27,760 to 75,714 times the weight of their shells. “According to these results, an oyster would appear to be a pumpingmachine of extraordinary activity..… “It is also known that in the testacea there is a continual current of water from behind forwards within the mantle..… “This current of water in the oysters appears to be astonishing when we compare it with the quantity of fluid which passes through the human body. “When a man weighing 150 lbs. consumes even 5 lbs. of liquid daily during a period of seventy-five years, still a quantity of liquid, only 912'5 times the weight of his body, would pass through his organism, or only about of the sea water which has passed through the oysters.”

note * page 93 Gmelin, Chemistry, vol. ii. p. 191, states:—” In hot climates, as on the west coast of Africa, where the water of the rivers highly charged with organic matter, mixes with the sea water which contains salts of sulphuric acid [sulphates], the same decomposition takes place, extending sometimes to a distance of 27 miles from the mouths of the rivers, the water containing hydrosulphurie aeid, sometimes as much as six cubic inches to a gallon.” This is confirmed from samples of water, which we have examined, taken from the roadstead at Monte Video by the telegraph ship “Seine.” It consists of a mixture of fresh and salt water, with a considerable amount of organic matter which has decomposed the sulphate, giving rise to a large amount of hydrosulphurie acid.

note * page 98 See Dittmar, Pkys. Ckem. Chall. Sep., Part

note * page 97 Reid, , Trot. Roy. Soc. Edin., vol. xv. pp. 151–157, 1888; Appendix, p.108.Google Scholar

note * page 100 Murray, , “Total Animal Rainfall of the Globe,” Scottish Geog. Magazine, vol. iii. p. 65, 1887.CrossRefGoogle Scholar