§ 44G. THE SPECIFIC GRAVITY OF THE SEA, ETC. 223 



go^ indicate that the seas of the southern do outweigh in specific 

 gravity the seas of the northern hemisphere in the proportion of 

 1.0272 to 1.0262 of specific gravity.''^ Daubeny, Dove, et al, have 

 pointed out an excess of salt contained in sea water south of the 

 equator, as compared with that contained in sea water north. 



447. These indications, as far as they go, and this view of the 

 Testimony of the hy- subjcct, whatcvcr future iuvcstigatious may show to 

 fhrai?cro°sstngTft ^^ ^^s truc worth, sccm to lean in support of the idea 

 the calm belts. advauccd aud maintained by facts and arguments 

 in Chapter IV., viz., that the southern seas are the boiler and the 

 northern hemisphere the condenser for the grand atmospherical 

 engine, which sucks up vapor from the south to feed the northern 

 hemisphere with rains. If it be true — and Dove also thinks it is 

 — that the clouds which supply our fountains with rains for the 

 great American lakes, and with rains for the majestic water- 

 courses of Europe and Asia, ISTorthern Africa and America, are 

 replenished from seas beyond the equator, then the w^aters of the 

 ocean south should be a little Salter, and therefore specifically a 

 little heavier, parallel for parallel, and temperature for tempera- 

 ture, than the waters of cis-equatorial seas. We begin to find that 

 the hydrometer is bearing testimony in support of the evidence 

 adduced in Chapters lY. and YII., to show that when the trade- 

 winds meet and rise up in the equatorial calm belt, the atmosphere 

 which comes there as southeast trade-winds passes with its vapor 

 over into the northern hemisphere. We had not anticipated that 

 this little instrument could throw any light upon this subject ; but 

 if, as it indicates, the sea water of the other hemisphere be Salter 

 and heavier than the sea water of this, what makes it so but evap- 

 oration, and what prevents currents from restoring its equilibrium 

 but the winds, which are continually sucking up vapor from the 

 brine of trans-equatorial seas, and pouring it down as fresh water 

 upon cis-equatorial seas and land ? It is taking out of one scale of 

 the balance and putting into the other ; and the difierence of spe- 

 cific gravity between the sea water of the opposite hemisphere may 

 give us a measure for determining the amount of fresh water that 

 is always in transitu. Certainly, if evaporation and rains were to 

 cease, if the rivers were to dry up, and the sea-shells to perish, the 



* According to Dr. Marcet, the southern ocean contains more salt than the north- 

 em in the proportion of 1.02919 to 1.02757. 



