Thalassa; an essay on the depth, temperature, and currents of the ocean . at or near the surface,and form strata of a temperature lower than that of the stratabeneath. It will appear from the previous remarks that the distributionof temperature in the ocean depends, as a general rule, upon aconstant supply of heat at the surface and a constant supply ofcold at the bottom; and the temperature-curve will representa series of gradually decreasing temperatures from the surfacetowards the bottom, as in Fig. 1. In those regions where thesupply of heat is reduced to a minimum, as we find is the casei
Thalassa; an essay on the depth, temperature, and currents of the ocean . at or near the surface,and form strata of a temperature lower than that of the stratabeneath. It will appear from the previous remarks that the distributionof temperature in the ocean depends, as a general rule, upon aconstant supply of heat at the surface and a constant supply ofcold at the bottom; and the temperature-curve will representa series of gradually decreasing temperatures from the surfacetowards the bottom, as in Fig. 1. In those regions where thesupply of heat is reduced to a minimum, as we find is the casein the higher latitudes, the stratum of cold water will be reachedwithin a short distance from the surface (Fig. 2, Curve C, andFig. 7), and in some parts of the ocean it may be said to occupythe whole depth of the sea (Fig. 8, Curve A). On the otherhand, where, as in the cases mentioned above, the supply of coldis reduced or entirely cut off by submarine barriers, the tem- 7. 1- < z -1 UJ h- a: < I h- oc O o 1- , z C) ©< rr t It- < o z OC 1113 OC. O H Z< < IHDO CO o o 12 1 do r^ o y— d o ^-^^— <o .^ U 1 1 1 1 1 1 1 1 1 1 1 V °o 0 Deductions from the Curve. 41 perature will remain stationary at or near the level of theobstruction, and the stratum of warm water will extend to thebottom, and thus fill up the whole space between the surfaceand the bottom, whatever may be the depth of the basin(Plate 16). This constant supply of heat and of cold is effected, as is wellknown, through the agency of currents. The latter are by nomeans an exceptional phenomenon confined to certain parts ofthe ocean. Varying in volume and velocity until they attainthe proportions of gigantic rivers flowing at a rate of severalmiles an hour, they occupy every part of the ocean, no part ofwhich can be said to be in a condition of absolute rest. Com-bined together they form, like the currents in the atmosphere,and in intimate association with the latter, a complete system ofcircul
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Keywords: ., bookcentury1800, bookdecade1870, bookidthalassa, booksubjectocean
