388 PHYSICAL GEOGKAPHY OF THE SEA, AND ITS METEOROLOGY. 



look with mucli interest for a description of the ' currents ' in 

 this part of the ocean." In latitude 38° south, longitude 6° east, 

 he found the water at 56^. His course thence was a little to the 

 south of east, to the meridian of 41° east, at its intersection with 

 the parallel of 42° south. Here his water thermometer stood at 

 50^, but between these two places it ranged at 60° and upward, 

 being as high on the parallel of 89° as 73°. Here, therefore, 

 was a stream — a mighty " river in the ocean " — one thousand 

 six hundred miles across from east to west, having water in the 

 middle of it 23° higher than at the sides. This is truly a Gulf 

 Stream contrast. What an immense escape of heat from the 

 Indian Ocean, and what an influx of warm water into the frozen 

 regions of the south ! This stream is not always as broad nor 

 as warm as Captain Grant found it. At its mean stage it con- 

 forms more nearlv to the limits assigned it in the diagram 

 (Plate IX.). 



751. Instances of commotions in the sea at uncertain intervals 

 Commotions in the ^ro uot unfroquent. There are some remarkable 

 ^^*- disturbances of the sort which I have not been able 

 wholly to account for. Near the equator, and especially on this 

 side of it in the Atlantic, mention is made, in the '*' abstract log," 

 by almost every observer that passes that way, of " tide-rips," 

 which are a commotion in the water not unlike that produced by 

 a conflict of tides or of other powerful currents. These " tide- 

 rips " sometimes move along with a roaring noise, like rifts 

 over rocks in rivers, and the inexperienced navigator always 

 expects to find his vessel drifted by them a long way out of her 

 course ; but when he comes to cast up his reckoning the next 

 day at noon, he remarks with surprise that no current has been 

 felt. 



752. Tide-rips present their most imposing aspect in the equa- 

 Humboidt'sdescrip- torial rogious. Humboldt met some in 34° N., 

 tion of tide-rips. ^ud thus doscribcs them : " When the sea is per- 

 fectly calm, there appear on its surface narrow belts, like small 

 rivulets, and in which the water runs with a noise very percep- 

 tible to the ear of an experienced pilot. On the 1 5th of June, in 

 about 34° 36' N.; we found ourselves in the midst of a great 

 number of these belts of currents ; we were able to determine 

 their direction by the compass. Some were flowing to the N.E. ; 

 others E.N.E., although the general motion of the ocean, indi- 

 cated by a comparison of the log and the longitude by chrono- 



