44 Temperature of the Ocean. 



fathoms at Station 159, and rose again to 500 fathoms at Station 

 160, so that between Stations 159 and 160, the "Challenger" 

 must have crossed the axis of a current about 500 fathoms deep, 

 and from 500 to 600 miles broad. This current, coming from 

 the Indian Ocean, flows in a south-easterly direction to the 

 southward of Australia, and penetrates into the Antarctic region 

 along the meridian of New Zealand. 



Fig. 7 presents a section, at Station 318, of the great 

 Antarctic current which flows as an under-current along the 

 east coast of South America, crosses the Equator, and pene- 

 trates into the North Atlantic. At the above station it rises to 

 within 100 fathoms of the surface. The steep gradient between 

 the surface and 100 fathoms is due to a branch of the Brazilian 

 current, which flows in a southerly direction towards the Falk- 

 land Islands. 



Curve A, Fig. 8, furnishes a similar example of the presence 

 of a cold stratum at the depth of little more than 100 fathoms 

 from the surface. It is the temperature-curve of Station 147, 

 near the Crozet Islands. Curve B illustrates the case of a cold 

 surface-stratum, probably formed by melting ice, observed in 

 the vicinity of the Antarctic Circle. The temperature falls 

 from — 1°.2 C. at the surface to — 1°7 C. at 50 fathoms, but 

 rises to — o°.8 C. at 200 fathoms, o°.o C. at 300 fathoms, and 

 o°.4 C. at a depth of 500 fathoms (Plates 12 and 13), 



Figs. 9 and 10 represent the conditions of temperature near 

 the Equator in the Atlantic and Pacific Oceans. The curve 

 of Fig. 9 belongs to Station 110, near St. Paul Rocks; the 

 curve of Fig. 10 to Station 221, in the basin between Papua 

 and the Caroline Islands. In the former a surface-current, 

 retaining a nearly uniform temperature of 25° C. down to a 

 depth of 30 fathoms, is joined by a steep gradient to an 

 intermediate current which extends from 100 fathoms to 400 

 fathoms, the cold bottom-stratum being reached at a depth of 



