Retrospective Criticism. 99 



from that gentleman, which, without invalidating my assertion, are not 

 without importance. 



From tht difference between an insular and a continental situation, it can 

 be easily understood why the climate of continental India within the tro- 

 pics is so infinitely hotter thini that of the islands of the West Indies ; 

 hence it can be a matter of little surprise to j'our readers, to find produc- 

 tions flourishing in the one, which can hardly be brought to grow in the 

 other. This simple fact will account for the appareiitly conflicting testi- 

 monies of your correspondent J. A. M. and myself respecting the grapevine, 

 I employ the term grape vine to distinguish the Titis vinifera fi^om other 

 climbing plants, to which the term vine is commonly applied, as a kind of 

 generic name, throughout the British West India islands. 



But even in India, it appears from j^our correspondent's statement, in his 

 communication of the 28th of last October (Vol. IV. p. 553.), that there 

 are situations within the tropics, even in India, where " grapes come to the 

 greatest perfection," notwithstanding their want of the repose of winter, — 

 the very fact which it was my object to establish. The fact appears to me 

 to be, that it is not the want of ivinter rest, but the want of some effectual 

 check to an overluxuriant vegetation, which renders the generality of extra- 

 tropical fruit trees barren within the tropics ; sinpe in the cooler situations 

 even of continental America, where the vigour of vegetation is considerably 

 less than in the hotter and lower regions, the peach, the apple, and other 

 European fruits, attain as high a perfection as with us. Even wheat can be 

 cultivated, as I have the authority of Humboldt for stating, in some situa- 

 tions within the tropics, with infinitely more advantage than among us ; 

 it may even be cultivated at elevations favourable to the culture both of 

 the cane and the coffee; and at " Venezuela and in the Island of Cuba, the 

 lower limit of wheat descends in the most unexpected manner towards the 

 burning plains of the coast." (Hiimb. Pei's. Narr.,yo\. vi. p. 505-6.) Wheat 

 is even cultivated in several parts of equinoctial America in places not more 

 than from 1727 to 1918 ft. above the level of the sea, "amidst the cultiva- 

 ation of coffee trees and sugar cane, and in places when the mean tempera- 

 ture of the year is at least 25" (77° Fahrenheit)." (p. 205.) 



" An acre (about 1^ acre English) near Victoria generally yields from 

 5,000 to 5,200 lbs. weight of wheat. The average produce is consequently 

 here, as at Buenos Ayres, three or four times as much as that of northern 

 countries. Nearly sixteen times the quantity of the seed is reaped." (vol.iv. 

 p. 106.) " Near San Mateo we find the last fields of wheat, and the last 

 mills with horizontal hydraulic wheels. A harvest of twenty for one was 

 expected ; and, as if the produce were but moderate, I v/as asked whether 

 corn produced more in Prussia and in Poland. It is an error that generally 

 prevails under the tropics, to consider grain as plants which degenerate in 

 advancing towards the equator; and to believe that the harvests are more 

 abundant in the northern climates." (p. 109-10.) " 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 attended with an excess of drought or moisture. To this circumstance 

 no doubt we must attribute the apparent anomalies that are sometimes ob- 

 served between the tropics, in the inferior limit of corn. We are astonished 

 to see to the east of the Havannah, 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 Xalapa, at 677 

 toises (4529 English ft.) of height, the luxury of vegetation is such, that wheat 

 does not form ears." (p. 1 1 1 .) 



As your correspondent may retort upon me, that Wheat and the Cerea- 

 lia, being annuals, have nothing to do with the question of plants which are 

 perennial requiring the repose of winter to recruit their powers, I shall not 



H 2 



