THE ACTINOMETRY OF THE SEA. 455 



890. As evaporation goes on by day or night, tlie upper stratum 

 Actinic processes, is rendered heayier by reason of both the heat and 



the fresh water borne away by evaporation; the upper water 

 having been thus rendered both Salter and cooler, has its specific 

 gravity increased so much the more. On the other hand, the strata 

 below, recei\dng more heat by day than they dispense again by 

 radiation day and night, grow actually warmer and specifically 

 lighter; and thus, by unseen hands and the '' clapping of the 

 waves," the waters below are brought to the surface, and those on the 

 surface carried down to unknown depths ; and thus, also, we discover 

 new and strange processes which have been ordained for the waters 

 of the ocean in their system of vertical circulation. 



891. Thus we arrive at the conclusion that the ocean is the 

 The reservoirs of gTcat rescrvoir of seusiblc as the clouds are of latent 

 ^^^^- heat. That in these two chambers it is innocuously 

 stored, thence to be dispensed by processes as marvellous as they 

 are benignant and wise, to perform its manifold offices in the 

 economy of our planet ; it is this heat which gives " liis circuits " 

 to the winds and chculation to the sea ; it is it that fetches from the 

 ocean the clouds that make " the earth soft mth showers." Stored 

 away in the depths of inter-tropical seas, it is conveyed along by 

 " secret paths " to northern climes, there to be brought to the sm^- 

 face in due season, given to the winds, and borne away to temper 

 the climates of western Em'ope, clothing the British Islands as they 

 go, in green, and causing them to smile under the genial warmth 

 even in the dead of winter. 



892. Thus perhaps we discover a new office for the waves in 

 An office for waves tlio physical ccouomy of the ocean. Is it not to 

 in the sea. thcui that has been assigTied the task of bringing up 

 by their agitation of the smface the layers of warm water that are 

 spread out below ; and are they not concerned also, as they draw up 

 the genial waters, in regulating the supply of heat for the winds 

 by night, as well as in cold or cloudy days, for the pm-poses of 

 evaporation ? Thus even the waves of the sea are made by this 

 beautiful study to present themselves as parts, important parts, in 

 the terrestrial machinery. We now view them as it were, like 

 balance-wheels in the comphcated system of mechanism by which 

 the climates of the earth are governed. If the waves did not 

 stir up the heated waters from below (§ 881), the winds would 

 evaporate slowly by night, for the want of adequate supphes of 

 caloric ; the consequence would be less precipitation and a more 



