352 Meteorological and Hydrographical 



both, "while the specific gravity on the 14th was 1-02770, al- 

 most identical with what it had been the previous day. 



About mid-day on the 15th the ship again seems to have 

 run into a current, setting to the NW, for the specific gravity 

 of the water had then increased to 1-02802 ; the following day 

 it was 1-02814, and on the 17th 1.02811 ; the set of the cur- 

 rent up to noon of the 16th was, N. 63° W., twenty-two miles ; 

 on the 17th, N. 15° W., twenty-four miles, and on the 18th, 

 N. 55° W., twenty-one miles. The extraordinary similarity in 

 the direction and velocity of this current, and in the specific 

 gravity of the water, with that experienced on the 12th and 

 13th, obviously shew a community of origin : whether this 

 current were continuous from 20° to 24° N., and Avas merely 

 covered by another of less specific gravity, flowing to the north 

 and east, is impossible to say ; but it is a subject deserving 

 farther investigation. 



It is worthy of observation, that the specific gravity of the 

 water increased considerably on the 16th Avhile in the current ; 

 the temperature, too, fell l°.l, and on the following day the 

 decrease of temperature was 3°-5, the specific gravity remain- 

 ing nearly the same. Accompanying these, there was a re- 

 markable change in the direction of the current on the 16th 

 and 17th, Avhich was much more to the northward than on 

 either the preceding or following days. The increase of spe- 

 cific gravity, and rapid diminution of temperature, would in- 

 dicate that water from a considerable depth was directed to 

 the surface by some inequality of the bottom, while the water, 

 being heaped up over the obstruction, would naturally flow off 

 to either side ; and hence the more northerly direction of the 

 current on the 16th and 17th. Any one may have a familiar 

 illustration of this by watching the eddies produced in a small 

 stream by the stones at its bottom. 



The distribution of temperature during the summer, over 

 the space occupied by these currents, is remarkable. The fol- 

 lowing observations, made by Mr Battersby, 47th regiment, in 

 September 1841, indicate that the north-easterly current has 

 then a temperature considerably higher than the NW. one on 

 either side of it. The error of the thermometer employed has 

 been eliminated. 



