Book II. AGRICULTURE UNDER VARIOUS CIRCUMSTANCES. 205 



1235. As elevation is knoivn to lessen 

 temperature in regular gradation ac- 

 cording to the altitude above the sea, 

 its influence on plants and animals 

 must correspond. Three hundred feet 

 in height are considered nearly equal 

 to half a degree of latitude, and occa- 

 sion a difference of temperature of 

 nearly twelve degrees of Fahrenheit. 

 Hence it is that the agriculture of the 

 temperate may sometimes be adopted in 

 the torrid zone, and that some of the 

 mountains of Jamaica will produce be- 

 tween their base and summit, almost all the plants of the world. Hence, also, that 

 even in the limited extent of the island of Britain, a given elevation on mountains in 

 Devonshire will be adapted for a different agriculture to the same elevation on the 

 Cheviot, Grampian or Sutherland mountains ; and while wheat ripens at six hundred 

 feet above the level of the sea in Cornwall, oats will hardly ripen at that height in the 

 Western isles. 



1 236. Elevation exposes plants and animals to the powerful operation of wind, and in 

 this respect must influence the disposition of the fields, fences, plantations, and buildings 

 of the agriculturist, as well as the plants and animals cultivated. It has some influence 

 also on the density of the air and the supplies of water and vapour, and even in these 

 respects must affect the character of the agriculture. In Switzerland and Norway the 

 upper mountain farms are completely above the mere dense strata of clouds, and their oc- 

 cupiers are often for weeks together without getting a view of the plains or valleys below. 



1237. That soil must influence the agriculture of a country appears at first sight very 

 obvious ; though if climate be favorable, time and art will render the soil fit for any 

 species of culture. Naturally, however, soil has a powerful influence ; and the period 

 under ordinary management will be considerable, before strong deep clays on a flat 

 surface, can be rendered equally fit for the turnip or potatoe, with friable loams, or more 

 gravelly or sandy soils. 



1238. The influence of moisture on the state of lands, is naturally very considerable, 

 and though draining and irrigation can effectually remove excess or supply deficiency, 

 yet fen lands and chalk hills, such as we find in Huntingdonshire, Surrey, and other 

 counties, will ever have a peculiar character of agriculture ; the marsh perennial hay 

 grasses will be the characteristic plants of the former, and saintfoin of the latter. 



1239. As the general result of this outline of the influence of physical circumstances on 

 agriculture, we may form a classification of that of any particular country to whichever 

 of the four universal divisions (1228. to 1231.) it belongs. We submit the following : 



1240. The agriculture of water-fed lands, including fens, marshes, and marsh 

 meadows. 



1241 . The agriculture ofsun-humt lands, including chalk, gravel, and sandy hills, where 

 vegetation is annually more or less burned up during two or more of the summer 

 months. 



1 242. The agriculture of mountains, in which the farmery is placed on the farm, as 

 distinguished from those cases in which the mountain lands or a part of them are appended 

 to lands on the plain. 



1243. Common agriculture, or that of the plains, valleys, and hills of a country in which 

 all the crops and all the animals suitable tp the climate may be profitably cultivated and 

 reared. 



Chap. III. 



Agriculture as affected by Civil, Political, and Religious Circumstances. 



1 244. The influence of the state of society and government on agriculture, nmst obviously 

 be very considerable, as well as climate and situation ; for it will signify little what a 

 country is capable of producing, if the inhabitants are too barbarous to desire, too igno- 

 rant to know, or too much oppressed to attain these products. Some of the finest 

 lands in the world, capable of producing wheat, maize, rice, and the grape, are in- 

 habited by savages, who live on game, wild fruits, or native roots ; or by half civilized 

 tribes who cultivate maize, and yams, or some other local root. Even in Ireland, 

 where the soil is better than in Britain, and with very moderate culture will produce 

 excellent wheat and other corns, with beef, mutton, and wool, the greater part of the 

 inhabitants from ignorance, oppression,, and in part as we have seen (840. J religious 



