§ 401. CUKRENTS OF THE SEA. 295 



ished and restored to their rounds in the wonderful system of 

 oceanic navigation. 



401. There are also about the equator in this ocean some curi- 

 Equatoriai currents, ous currcnts, which I havc Called the " Doldrum 

 Currents" of the Pacific, but which I do not understand, and as to 

 which observations are not sufficient yet to afford the proper ex- 

 planation or description. There are many of them, some of which 

 at times, run with great force. On a voyage from the Society to 

 the Sandwich Islands I encountered one running at the rate of 

 ninety-six miles a day. These currents are generally found set- 

 ting to the west. They are often, but not always, encountered in 

 the equatorial .Doldrums on the voyage between the Society and 

 the Sandwich Islands. In Captain Pichon's abstract log of the 

 French corvette " L'Eurydice," from Honolulu to Tahiti, in Au- 

 gust, 1857, a " doldrum" current is recorded at 79 miles a day, 

 west by north. He encountered it between 1° N. and 4° S., where 

 it was 300 miles broad. On the voyage to Honolulu in July of 

 the same year, he experienced no such current ; but in 6° IST. he 

 encountered one of 36 miles, setting southeast, or nearly in the 

 opposite direction. This current does not appear to have been 

 more than 60 miles broad. What else should we expect in this 

 ocean but a system of currents and counter-currents apparently 

 the most uncertain and complicated ? The Pacific Ocean and the 

 Indian Ocean may, in the view we are about to take, be consid- 

 ered as one sheet of water. This sheet of water covers an area 

 quite equal in extent to one half of that embraced by the whole 

 surface of the earth ; and, according to Professor Alexander Keith 

 Johnston, who so states it in the new edition of his splendid Phys- 

 ical Atlas, the total annual fall of rain on the earth's surface is 

 one hundred and eighty -six thousand, two hundred and forty cu- 

 bic imperial miles. Not less than three fourths of the vapor 

 which makes this rain comes from this waste of waters ; but sup- 

 posing that only half of this quantity, i. e., ninety-three thousand, 

 one hundred and twenty cubic miles of rain falls upon this sea, 

 and that that much, at least, is taken up from it again as vapor, 

 this would ^ive two hundred and fifty-five cubic miles as the 

 quantity of water which is daily lifted up and poured back again 

 into this expanse. It is taken up at one place and rained down 

 at another, and in this process, therefore, we have agencies for 



