230 PHYSICAL GEOGEAPHY OF THE SEA, AND ITS METEOEOLOGY. 



452. The hydrometer indicates the rainy latitudes at sea. — There is 

 another indication which this little instrument has afforded con- 

 cerning the status uf the sea, and which deserves notice. We 

 are at first puzzled with the remarkably light water between 9"^ 

 and 16^ S., Fig. 1, and in Fig. 2 between 7^ and 9^ N., as well as 

 in 19° N. But after a little examination, we are charmed with 

 the discovery that the hydrometer points out the rainy regions 

 at sea. Eodgers' observations on his homeward passage from 

 San Francisco to Cape Horn furnish the data for the curves 

 {Fig. 1) between 37° N. and 57° S. Now Plate YIII. shows that 

 the equatorial calm belt lies south of the line where it is inter- 

 sected by the homeward route from California. It also shows 

 that when he crossed the " Doldrums " in the Atlantic, that belt 

 was in north latitude about 7°-10°, and that when he was in 

 18°-20° N. (Fig. 2) he was then passing through the offiugs of 

 what are called the " Leeward Islands " of the West Indies, and 

 that these are rainy latitudes at sea — the first two being under 

 the cloud ring, the last being near the land in the trade-wind 

 region, and confirming the remark so often made concerning the 

 influence of islands at sea upon vapour, clouds, and precipitation. 



453. Astronomical view. — The most comprehensive view that 

 we are permitted to take of cosmical or terrestrial arrangements 

 and adaptations is at best narrow and contracted. Nevertheless, 

 in studying the mechanism which Wisdom planned and the Great 

 Architect of nature designed for the world, we sometimes fancy 

 that we can discover a relation between the difi'erent parts of the 

 wonderful machinery, and perceive some of the reasons and 

 almost comprehend the design which Omnipotent Intelligence 

 had- in view when those relations were established. Such fancies, 

 rightly indulged, are always refreshing, and the developments of 

 the hydrometer which we have been studying point us to one of 

 them. This fancied discovery is, that a sea of fresh water instead 

 of salt would not afford the compensations that are required in 

 the terrestrial economy, and we also fancy that we have almost dis- 

 covered a relation between the orbit of the earth and the arrange- 

 ment of land and water on its suiface and their bearing upon 

 climate. Onr planet passes its perihelion during the. southern 

 summer, when it is nearer the centre and source of light and heat 

 by more than three millions of miles than it is at its winter 

 solstice, so tliat, on the 1st of January, the total amount of heat 

 received by the earth is about -j^.- more than it receives during a 



