Book II. AGRICULTURE UNDER VARIOUS CIRCUMSTANCES. 20^ 



lierbage, for numerous annual weeds, and the cochineal cactus for the shewy but useless 

 Mesembryantheraums and Stapelias of the African wastes. These, however, are only 

 suggestions. 



1225. Culture in the north of jEwro;)e depends for the most part more on draining lands 

 of their superfluous water, than on artificial supplies of that element. When irrigation 

 is applied it is limited entirely to grass lands ; and that not for the purpose of supplying 

 such lands with moisture, but for stimulating by manure held in solution by the water, 

 and for increasing or maintaining heat. The greatest care is requisite to prevent this 

 mode of watering from proving more injurious than useful ; but little danger results 

 from the application of water in hot countries, and there it is valuable by moderating 

 rather than increasing the temperature of the soil. Water in the north of Europe is 

 generally supplied in more than suflScient quantity by the atmosphere ; and therefore one 

 great object of the cultivator is to keep the soil thoroughly drained by surface gutters 

 and subterraneous conductors ; to keep it pulverized for the moisture to pass through, 

 and the roots to extend themselves ; well stocked with manure to supply nourishment ; 

 freed from weeds, to prevent any of this nourishment from being wasted ; and to 

 admit the light, air, and weather to the useful plants. In the hot countries keeping the 

 soil free from weeds is generally a duty easily performed, and often rendered un- 

 necessary; for whenever water is withheld even in the south of Spain (724.), every 

 living thing is burned up with drought. It is remarkable that in the most northerly 

 parts of Europe and America the same effect, especially as to fibrous rooted perennials, 

 is produced by cold, and in Russia and New England, where there is scarcely any 

 spring, the agriculturist has only to plough once, and sow in the same way as in the 

 hot valleys of the south of Spain, and South America, where vegetation is equally rapid 

 from the accession of moisture as it is in the cold plains of Russia from the influence of 

 the sun during the long days of a northern summer. In hot countries putrescent 

 manures are not altogether neglected, but they are much less necessary than in cold 

 countries, and can be done without where there is abundance of water ; there water, 

 intense heat, and light, a consequent moist atmosphere, and a well pulverised soil, supply 

 very thing necessary for luxuriant vegetation. 



1226. Hence it is that agriculture considered geographically admits of two grand divisions, 

 that of the 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 belongs the greater part of Europe, the north of Asia, the north of America, and 

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

 great part of the south of America, and part of Australasia. As intermediate between 

 agriculture by waterings 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. 



1227. 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 in the mind of the practical agriculturist, we submit the following : 



1228. The agriculture of irrigation may be considered as extending thirty-five degrees 

 on each side of the equator. 



1229. The agriculture of manures and irrigation from the thirty-fifth to the forty-fifth 

 degree north and south of the equator. 



1230. The agriculture of draining and manures from the forty-fifth degree, north and 

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



1231. The arts of fishing and huntings as the only means of subsistence, from the sixty- 

 seventh degree, or arctic circle, to the pole. 



Chap. II. 

 Agricidture as influenced by Physical Circumstances. 



1232. The physical circumstances which prindpaUy affect agriculture are temperature 

 and light, elevation, moisture, and soil. 



1233. Temperature and light have tlie most powerful influence on the culture both of 

 plants and animals. Elevation, when not considerable, admits of being rendered sub- 

 servient to the processes of culture, and to the habits of different plants and animalsV 



