Irrigation, as employed by the farmer, is chiefly beneficial in proportion to the amount of saline and decomposing matter contained in solution by the water employed. But this is not the exclusive cause of benefit, for much of this arises from the increased and permanent supply of moisture to the roots of the plants. These can only derive food from the soil in a gaseous or liquid form; and the decomposing matters in a soil decompose, and constantly are I converted into gaseous and soluble matters,with a rapidity proportioned to the abundance of water supplied to them. Experience shows that there is in the kitchen garden scarcely a crop that is not benefited by a much more abundant supply of water than can be obtained usually ; and I can bear testimony to the correctness of Mr. Knight's conclusion, not limiting, however, my approval of such abundant watering to late crops of peas, but to all, as well as beans, spinach, and the entire cabbage tribe. Kidney beans and potatoes are not benefited by such an abundance of water.

"The quantity of water," says Mr. Knight, "which may be given with advantage to plants of almost every kind, during warm and bright weather, is, I believe, very much greater than any gardener who has not seen the result will be inclined to suppose possible; and it is greater than I myself could have believed upon any other evidence than that of actual experience.

"My garden, in common with many others, is supplied with water by springs, which rise in a more elevated situation; and this circumstance afforded me the means of making a small pond, from which I can cause the water to flow out over every part of every other kind through every part of the summer; and I cause a stream to flow down the rows of celery, and along the rows of brocoli and other plants, which are planted out in summer, with very great advantage. But the most extensive and beneficial use which I make of the power to irrigate my garden by the means above mentioned, is in supplying my late crops of peas abundantly with water, by which the ill effects of mildew are almost wholly prevented, and my table is most abundantly supplied with very excellent peas through the month of October".