Ill 



15° to 19° ; in Barbary, and in Egypt, from 27° 

 to 29° ; within the tropics, between fourteen and 

 six hundred toises of height, from 14 9 to 25*5° 

 of the centigrade thermometer. 



The fine harvests of Egypt and of the kingdom 

 of Algiers, those of the valleys of Aragua and 

 the interior of the island of Cuba, sufficiently 

 prove, that the augmentation of heat is not 

 prejudicial to the harvest of wheat and other 

 alimentary grain, unless it is attended with an 

 excess of drought or moisture. To tfiis circum- 

 stance no doubt we must attribute the apparent 

 anomalies, that are sometimes observed between 

 the tropics, in the inferior limit of corn # . We 

 are astonished to see to the East of the Havan- 

 nah, in the famous district of Quatro Villas, 

 this limit descend almost to the level of the 

 ocean ; while to the West of the Havannah, on 

 the slope of the mountains of Mexico and Xa- 

 lapa, at six hundred and seventy-seven toises of 

 height, the luxury of vegetation is such, that 



temperatures of the coasts at 23° and 45° of latitude. For 

 the basis of these calculations, see my Essay on the Distri- 

 bution of Heat in the M4m de la Soc. d"Arcueil % vol. iii, p. 

 516, 579, 602 : and above, vol. iii. p. 459. 



* Since our return to Europe, Mr. Caldas has collected a 

 great number of observations on this limit, in a memoir which 

 ought to be found among the papers of our illustrious friend, 

 Don Jose Celestino Mutis. See the Spanish translation of 

 my Geography of Plants, in the Semanario de N. Grenada, 

 vol. ii, p. 187. 



