250 Dr Davy on the Temperature of' the Sea and the Ai 



and on our beam, the ship went with great rapidity, at the 

 rate of twelve knots an hour. The effect of a vessel dashing- 

 through a sea of foam, brightly luminous, and emitting a sil- 

 ver light, was extremely beautiful and striking. The squall 

 was soon accompanied with heavy rain, which lasted till 

 about 10 h P. M. The rain then ceased, and the wind abated, 

 and was moderate during the rest of the night. 



May 16. N. Lat. D. R. 4° 13', W. Long. 19° 15'. 



A squall, which threatened us at 10 A. M., commenced 

 soon after, and lasted till noon. The wind was strong and va- 

 riable. Our main- top-sheet was torn to pieces. The accom- 

 panying rain was heavy. 



Between sunset and midnight, the weather was pleasant, the 

 breeze gentle, and the wake of the ship was remarkably lumi- 

 nous. The luminous appearance was unusual, being confined 

 to distinct oval luminous masses. Between midnight and sun- 

 rise, it was almost calm, and it rained the greater part of the 

 time very heavily. 



May 17. N. Lat. 6°, W. Long. 19° i*P. 



During the last forty-eight hours before noon, we have been 

 carried about twenty-two miles to the north, and about as 

 much to the north-east. 



The night was very fine, and the breeze very gentle. Both 

 now and formerly, I have observed the air warmer and drier 

 at nine or ten o'clock than just after sunset. 



8 



