73 



tables have all been collected under the same 

 parallels, but in very different longitudes and 

 seasons. At the time of the voyage to the Ma- 

 gellanick regions, and to Batavia, the maximum 

 of the temperature was found much more to the 

 north than it had been perceived in all the 

 other voyages ; which has had a sensible in- 

 fluence on the heat of the sea to the north of the 

 tropic of Cancer. The maximum, according to 

 Churruca and Rodman, was in October, in six 

 degrees north ; according to Mr. Quevedo, in 

 March, in 20° 2' south ; and according to Dr. 

 Perrins, in April, in 0° 15' north. I observed it 

 in March, at the east of the Galipago islands, in 

 2° 27" of north latitude. It is probable, that 

 changes in the currents cause these extraordi- 

 nary anomalies ; and that the great circle, which 

 passes through the points where the water of the 

 sea is the warmest, cuts the equator at an angle 

 which is variable according as the declination of 

 the Sun is north or south. These phenomena, 

 connected perhaps with those of the limit of the 

 trade winds, and the maximum of the saltness of 

 the sea, deserved to be carefully examined ; but 

 we should not be surprised at a failure of accu- 

 rate observations on the temperature of the 

 equatorial seas, if we recollect, that we are still 

 ignorant of the thermometrical variations in the 

 neighbouring seas of Europe *, 



* Since my return in 1804, I have in vain exhorted those 



