116 PHYSICAL GEOGRArHY OF THE SEA, AND ITS METEOROLOGY. 



sea on different sides of tlie line is reconciled by the hypothesis 

 which requires a crossing at the calm belts. The vapour which 

 conveys fresh water and caloric from the southern hemisphere to 

 the northern will in part account for this difference both of spe- 

 cific gravity and temperature, and no other hypothesis will. 

 This hydrometric difference indicates the amount of fresh water 

 which, as vapour in the air, as streams on the land, and as 

 currents in the sea,* is constantly in transitu between the two 

 hemispheres. All these facts are inconsistent with the supposi- 

 tion that there is no crossing at the calm belts, and consistent 

 with the hypothesis that there is. It is no argument against the 

 hypothesis that assumes a crossing, to urge our ignorance of any 

 agent with power to conduct the air across the calm belts. It 

 would be as reasonable to deny the red to the rose or the blush 

 to the peach, because we do not comprehend the processes by 

 which the colouring matter is collected and given to the fruit or 

 flower, instead of the wood or leaves of the plant. To assume 

 that the direction of the air is, after it enters the calm belts, left 

 to chance, would be inconsistent with our notions of the attri- 

 butes of the great Architect. The planets have their orbits, tho 

 stars their course, and the wind " his circuits." And in the con- 

 struction of our hypotheses, it is pleasant to build them up on 

 the premiss that He can and has contrived all the machinery 

 necessary for guiding every atom of air in the atmosphere 

 through its channels and according to its circuits, as truly and 

 as surely as He has contrived it for holding comets to their 

 courses and binding the stars in their places. These circum- 

 stances and others favouring this hypothesis as to these air- 

 crossings, are presented in further detail in Chaps. VII., IX., 

 XL, and XII., also §349. 



289. TJie atmosphere to he studied like any other machinery, hy its 

 operations. — In observing the workings and studying the offices of 

 the various parts of the physical machinery which keeps the 

 world in order, we should ever remember that it is all made 

 for its purposes, that it was planned according to design, and 

 arranged so as to make the world as we behold it : — a place for 

 the habitation of man. Upon no other hypothesis can the 

 student expect to gain profitable knowledge concerning the 

 physics of sea, earth, or air. Eegarding these elements of tlie 



* The water wliicli the rivers empty into the North Atlantic has to find its 

 way south Avitli the cm-rents of the sea. 



