B. TERRESTRIAL PIIYSIC3 AND METEOROLOGY. *j\ 



nominated by him the Alaska current, which had previously 

 been surmised from isolated observations and theoretical con- 

 siderations. Mr. Dall has been able to determine the rate and 

 dimensions of several portions of this current, and the maxi- 

 mum, minimum, and mean annual temperature. The exist- 

 ence of definite oceanic currents in the eastern half of Behr- 

 ing's Sea is shown to be very doubtful. Some important gen- 

 eralizations on the relations of the Pacific and Behrinsj's Sea 

 tides to each other are made, and the peculiarities of the 

 compound tides of this region are graphically indicated by 

 diagrams in a new method, original with the author, and pos- 

 sessing some interest for those studying these problems. The 

 report is accompanied by numerous hydrographic memoran- 

 da, and tables of meteorological, current, and tidal observa- 

 tions. 



ORIGIN OF OCEAN CURRENTS. 



Miihry, in a paper on the origin of ocean currents, states 

 that a difference of temperature in the equatorial and polar 

 regions of the ocean is not sufficiently powerful alone to bring 

 about the great hydrodynamic effect attributed to it, viz., the 

 existing phenomena of latitudinal circulation. This latter 

 is largely a result of the rotation of the earth, although the 

 thermal circulation is frequently of great importance. He 

 finds that the latitudinal oceanic circulation is to be consid- 

 ered as a duplicate one, that is, resulting from two causes 

 working in the same direction, the one being the general 

 diminution of gravitation toward the equator, and the other 

 the general elevation of temperature, with its consequent ex- 

 pansion of the sea-water, each circulation existing by itself, 

 independently of the others. The difference of density due 

 to a difference in the saltness of water, according to Miihry, 

 has no influence in the formation of currents. Zeitschrift fiir 

 3/eteorologie, IX., 282. 



THE CIRCULATION OF OCEAN CURRENTS. 



Dr. Carpenter calls attention to the researches on ocean 

 currents and deep-sea temperatures of Lenz,who accompanied 

 the Russian exploring expedition of Kotzebue in 1823-26, 

 and made a large number of observations of temperatures of 

 the ocean water with thermometers whose indications were 



