67 



It is very remarkable, that, notwithstanding' 

 the immensity of the ocean, and the rapidity of 

 the currents, there is a great uniformity every 

 where in the maximum of heat in the equinoc- 

 tial seas. Mr. Churruca found this maximum, 

 in 1788, in the Atlantic Ocean, at 28*7°; Mr. 

 Perrins, in 1804, at 28*2° ; Mr. Rodman *, in 

 his voyage from Philadelphia to Batavia, at 28*8°; 

 and Mr. Quevedo, at 28" 6°. In the South Sea I 

 observed it the same year at 29*3°; consequently, 

 the differences scarcely exceed 1° of the centi- 

 grade thermometer, or | 8 of the total heat. We 

 must recollect, that, under the temperate zone, 

 to the north of the parallel of 45°, the mean 

 temperatures of different years vary more than 

 2°, or a fifth of the quantity of caloric that a de- 

 terminate part of the Globe -j~ receives. 



* Coxe, Philadelphiai] Medical Museum, vol. i, p. 83. 



t Geneva from 1796 to 1809; 7-87° : 834°; 8<> ; 7*47 0 ; 

 8'38* ; 8-49°; 8*49°; 8 27° ; 8*5°; 712°; 8-73°; 7*78°; 

 6*68°, and 7*54° of Reaumur's thermometer: Paris, at the 

 Observatory, from 1803 to 1810; 11*95° j 10*75 # j 10*36*; 

 10-55*; 1050°; 10*65°; 1110°; and 9*79° of the centi- 

 grade thermometer. In proportion as we approach the tro- 

 pics, the variations of the annual temperature diminish. 

 Rome (lat. 41° 53'). from 1789 to 1792 ; 13*6° ; 12*5° ; 13*4° j 

 and 12-9°, Reaum. (Buch. in Gilbert's Annalen der Physik, t. 

 24, p. 238). Philadelphia, (lat 39* 56') from 1797 to 1803. 

 12 7°; 11*6°; ll'8q; 11*7°; 12*7°; and 12-8° of the centi- 

 grade thermometer. From these very accurate observations 

 it results, that the extremes at Geneva have been 2*5° ; at 

 Paris 2*2° ; at Rome, 1-3° ; and at Philadelphia, Pl 0 of the 



