In treating of the advantages of greater facilities for irrigation in India, I do not recollect ever having seen any mention made of that of penetrating by wells into the deep deposits below of the soluble salts, or their bases, and bringing them to the surface in the water, for the supply of the plants, shrubs, and trees we require.  People talk of digging for valuable metals, and thereby “developing resources;” but never talk of digging for the more valuable solutions of soluble salts, to be combined with the organic acids already existing in the soil, or provided by man in manures—­and with the carbonic acid, ammonia, and water from the atmosphere—­to supply him with a never-ending succession of harvests.  The practical agriculturists of Oude, however, say, that brackish water in irrigation is only useful to tobacco and shama; and where the salts which produce it superabound, rain-water tanks and fresh-water rivers and canals would, no doubt, be much better than wells for irrigation.  All these waters contain carbonic acid gas, atmospheric air, and solutions of salts, which form food for plants, or become so when combined with the organic acids, supplied by the decayed animal and vegetable matter in the soil.

Soils which contain salts, which readily give off their water of crystallization and effloresce, sooner become barren than those which contain salts that attract moisture from the air, and deliquesce, as chlorides of calcium and magnesia, carbonates and acetates of potassa, alumina, &c.  Canals flowing over these deep dry beds, through which little water from the springs below ever percolates to the surface, are not only of great advantage for irrigating the crops on the surface, but for supplying water as they flow along, to penetrate through these deep dry beds; and, as they rise to the surface by capillary attraction, carrying along with them the soluble salts which they pick up on their way.  In Oude, as in all the districts that extend along to the north of the Ganges, and south of the Himmalaya chain, easterly winds prevail, and bring up moisture from the sea of the Bay of Bengal.  All these districts are, at the same time, abundantly studded with groves of fine trees and jungle, that attract this moisture to the earth in rain and dew.  Through Goozerat, Malwa, Berar, and Bundelkund, and all the districts bordering the Nerbudda river, from its mouth to its sources, westerly winds prevail, and bring up moisture from the Gulf of Cambay; and these districts are all well studded with groves, &c., and single trees, which act in the same manner, in attracting the moisture from the atmosphere to the earth, in rain and dew.  In Rajpootana and Sinde no prevailing wind, I believe, comes from any sea nearer than the Atlantic ocean; and there are but few trees to attract to the earth the little moisture that the atmosphere contains.  The rain that falls over these countries is not, I believe, equal to more than one-third of what falls over the districts, supplied