104 On Similarities in the 



well repay the trouble of the investigation. The counter 

 equatorial current is particularly interesting, and its dynamics 

 obscure. Its range is very superficial, and its physical condi- 

 tions can be studied without the elaborate and costly equipment 

 required for the research of oceanic depths. 



With the change of season the counter equatorial current 

 shifts its latitude, but within narrow limits. It seems never 

 to be met with south of the equator and rarely south of lat. 4 N. 

 Its extreme fluctuations are between 4 N. and 12 N., and for 

 the greater part of the year it occupies the zone between 

 7 and 9 N. where it has impressed its mark on the distribution 

 of temperature in the water below it. In Diagram B, where 

 the lines of true density coincide closely with the isothermal 

 lines, we see the isothermal of 50 (coinciding with 1-027) 

 approach within no fathoms of the surface at the station 

 in lat. 9 28', and it falls away to below 200 fathoms on both 

 sides. The thick line passing unconformably through the 

 above shows the extent to which the concentrated waters of 

 the south-east trade wind district penetrate. To the left 

 hand or north of this line all the water is at a density (at 60 F.) 

 below 1-026. The water is diluted both by diffusion of the 

 rain water above and the rising of abysmal water from below 

 without mixture with any concentrated surface water. 



In the Western Pacific on the voyage from Admiralty 

 Island to Japan in March, the "Challenger" passed through 

 no similar easterly current, but here it is probably completely 

 checked by the strength of the north-east monsoon and may be 

 much intensified at the other seasons by the south-east monsoon. 



The temperature observations showed the enormous amount 

 of highly heated comparatively dense water flowing at this 

 season steadily westward towards the Indian Ocean. In its 

 progress from the meridian of 150 W. to that of 145 E. 

 the westerly stream has taken up an enormous amount of heat. 

 The velocity of the western current is not so great, but its 

 axis lies in the same latitude, namely between 2 and 3 N. 

 The surface temperature is over 83 F., and at 90 fathoms 

 the temperature of the water is still above 80. Between 

 these depths the water has on an average a temperature about 



