204 HISTORY OF AGRICULTURE. Part I. 



intense heat, and light, a consequently moist atmosphere, and a soil well pulverised by art, 

 supply every thing necessary for luxuriant vegetation. 



1 252. Hence it is that agriculture considered geographically admits of two grand divisions : 

 that of tlie cold climates, which may be called agriculture by draining and manures ; 

 and that of the hot climates, which may be called agriculture by irrigation. To the 

 former belong the greater part of Europe, the north of Asia, the north of America, 

 and part of the Australian isles ; to the latter, Egypt, Persia, India, China, Africa, 

 great part of the south of America, and part of Australia. As intemiediate between 

 agriculture bi/ watering, and agriculture by draining, may be mentioned that mixed culture 

 by watering and manuring which prevails in the south of France, Spain, and Italy ; and 

 as opposed to the aquatic culture of the torrid zone, may be placed the rural economy of 

 the arctic circle, which, from the prevalence of cold and ice, precludes all culture of the 

 soil, admits little else than the growth of mosses and lichens, and is therefore limited to 

 fishery and the chase. 



1253. These leading divisions of culture are by no means so absolute as to be determinable 

 by degrees of latitude, so much depending on physical circumstances, as elevation, soil, 

 aspect, island or continent, &c. ; but as an approximation which may impress some 

 general ideas on the mind of the practical agriculturist, we submit the following : 



1254. The agriculture of irrigation may be considered as extending thirty-five degrees 

 on each side of tlie equator. 



1255. The agriculture of manures and irtigation from the thirty-fifth to the forty-fifth 

 degree north and south of the equator. 



1256. The agriculture of draining and manures from the forty-fifth degree, north and 

 south of the equator, to the sixty-seventh degree or polar circle. 



1257. The arts of fishing and hunting, as the only means of subsistence, from the sixty- 

 seventh degree, or polar circle, to the pole. 



Chap. II. 

 jigriculture as influenced by Physical Circumstances. 



1 258. The physical circumstances which principally affect agriculture are temperature, 

 light, elevation, moisture, and soil. 



1259. Temperature and light have the most powerful influence both on the culture of 

 plants and rearing of animals. Elevation, when not considerable, admits of being ren- 

 dered subservient to the processes of culture, and to the habits of different plants and 

 animals ; moisture may be moderated or increased, soil improved, but temperature and 

 light are in a great measure beyond human control. Hence it is that the plants and ani- 

 mals under the management of the husbandman do not altogether depend on his skill or 

 choice, but on his local situation. Not only the maize, rice and millet, which are such 

 valuable crops in Asia and Africa, are incapable of cultivation in the north of Europe ; 

 but even within the extent of the British isles, some kinds of grain, pulse, and roots can- 

 not be grown to such perfection in certain districts as in others. Thus the Angus variety 

 of oat will not come to the same perfection, south of London, that it does north of York ; 

 and, of tlifferent varieties, the Dutch, Polish, and potato oat will succeed better in a warm 

 climate, than the Angus, black, or moorland oat, which answer best for cold, moist, and 

 elevated districts. The turnip arrives at a greater size in Lancashire, Berwickshire, and 

 Ayrshire, than it does in Kent, Surrey, or Sussex, even adrtiitting the best possible manage- 

 ment in both districts. The pea requires a dry soil and climate, and more heat than the 

 bean, and consequently thrives much better in the south of England, in Kent, and Hamp- 

 shire, than in Scotland or Ireland. Hops cannot be cultivated advantageously in Scotland, 

 nor clover seeds, except, perhaps, in a few very favourable situations. Even wheat does 

 not come to maturity in many parts of that country in ordinary seasons. It is certain 

 that the perennial grasses thrive best where the temperature and light are moderate through- 

 out the year, as on the sea-coast in various countries, where mildness is obtained from 

 the influence of the sea, and light from the absence of a covering of snow ; and also in the 

 south of England, where the snow seldom lies, and where the temperature is moderate, 

 and the nights not so long as they are farther north. It is equally certain that in 

 America and Russia, where the cold is intense during winter, and the plants on the sur- 

 face of the ground are deprived of light for six or seven months together by a covering 

 of snow, all lierbaceous vegetation is destroyed. Contrasted with these facts may be 

 mentioned, as equally well ascertained, that annual plants in general attain a greater 

 bize, and a higher degree of perfection, where the winters are long, and the Siunmers hot 



