§ 890. THE ACTINOMETRY OF THE SEA. 473 



The reservoirs of heat, great leservoir of Sensible, as the clouds are of la- 

 tent heat; that in these two chambers it is innocuously stored, 

 thence to be dispensed by processes as marvelous as they are be- 

 nignant and wise, to perform its manifold offices in the economy 

 of our planet. It is this heat which gives " his circuits" to the 

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

 ocean, the clouds that make " the earth soft with showers." Stored 

 away in the depths of intertropical seas, it is conveyed along, by 

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

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

 the climates of Western Europe, clothing the British Islands as 

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

 warmth even in the dead of winter. 



890. We may note, also, another peculiarity as to the differ* 

 The radiating powers eucc in the dircct heat-absorbino; and radiatinsf 



ot earth, air, and wa- • n t i 



ter compared. propcrtics of sca, land, and air. It is one which 



presents the atmosphere in the light of a regulator between the 

 two on one hand, and the heating powers of the sun on the other. 

 It is suggestive, also, of other benign compensations and lovely 

 offices in the physical machinery of our planet. Both land and 

 water receive more heat .from the sun than they radiate again ; 

 but the atmosphere receives less heat direct from the sun than it 

 radiates off again in'o space. As the heat comes from the sun, 

 part of it is absorbed by the atmosphere, but the largest portion 

 of it is inipressed upon the land and water. From these a por- 

 tion passes off into the atmosphere by conduction, w^hile another 

 portion is radiated directly off into the realms of space. What 

 becomes of the remainder? Let us inquire, for there is a remain- 

 der ; and unless means for its escape were provided, the land and 

 water, especially the latter, would continue to grow warmer and 

 warmer, and so produce confusion in the terrestrial economy. 

 The remainder of this heat, being that which is neither radiated 

 by sea and land directly off into space, nor imparted to the air b}^ 

 conduction from them, is absorbed in the processes of evapora- 

 tion. It is then delivered to the atmosphere, latent in the vesicles 

 of vapor, to be set free in the cloud region, rendered sensible and 

 imparted to the upper air, whence it is sent off by radiation into 

 the " emptiness of space." Thus the air, with its actinometry, 

 presents itself in the light of a thermal adjustment, by wliich the 



