Dr. Davy on the Temperature of the Sea and the Air, 8fc. 79 



which are mostly angular, and arranged in the form of a star 

 with ten rays. 



Echinus esculentus. This animal is seldom or never thrown 

 ashore ; but it is taken in great numbers by fishermen when 

 dredging for oysters. 



When floating on the surface of the water, as I have seen 

 them on the coast of Fife, they may be approached with ease, 

 but they sink the moment they are touched, or disturbed by 

 the slightest rippling of the water. 



Spatangus canaliferus. Among some hundreds which I 

 have picked up, not more than two contained the living ani- 

 mal. Great numbers are often thrown ashore in Aberlady 

 Bay, about a furlong to the east of Gosford House, and more 

 sparingly on Portobello sands. 



Art. XII. — Observations on the Temperature of the Sea 

 and the Air, made during a Voyage from the Cape of Good 

 Hope to St. Helena, in 1820. By John Davy, M. D. 

 F. R. S. Communicated by the Author. 



It was our intention to have reimbarked early yesterday morn- 

 ing, but we were prevented by a strong SE. wind. It mode- 

 rated a little however in the afternoon, and we went on board. 

 We sailed the same evening by moonlight, the wind blow- 

 ing almost a gale. 



April 20. 



Air. Water. Hygr. Wind and Weather. 



12 h N. 64° 59° — SE. moderate, clear. Out of 



sight of land, water greenish. 



At daylight this morning no land was to be seen ; and at 

 noon the Captain was of opinion that we were not in soundings. 



It is a curious circumstance, that the temperature of the 

 sea near the Cape shore should be several degrees lower than 

 the mean annual temperature of the coast. 



The night was fine, and the breeze steady. 



