_Warping._--This name has been given to a method of improving soils by causing the water of rivers to deposit the mud it carries in suspension upon them, and which has been largely practised in the low lying lands of Lincoln and Yorkshire, where it was introduced about a century ago. It is most beneficial on sandy or peaty soil, and by its means large tracts of worthless land have been brought under profitable cultivation. It requires that the land to be so treated shall be under the level of the river at full tide, and it is managed by providing a sluice through which the river water is allowed to flood the land at high tide, and again to escape at ebb, leaving a layer of mud generally about a tenth of an inch in thickness, which it brought along with it. By the repetition of this process, a layer of several feet in thickness, of an excellent soil, is accumulated on the surface. Herapath, who has carefully examined this subject chemically, has shown that in one experiment where the water used contained 233 grains of mud per gallon, 210 were deposited during the warping. The following analyses will show the general nature of the matters deposited, and the change which they produce on the soil:--No. 1 is the mud from the Humber in its natural state, No. 2 a specimen of warp of average quality artificially dried, No. 3 a sandy soil before warping, and No. 4, the same fifteen years after having received a coating of 11 inches of mud. +---------------------------------+---------+--------+---------+--------+ | | 1 | 2 | 3 | 4 | | +---------+--------+---------+--------+ | Water | 47.49 | ... | 1.06 | 2.00 | | Organic matter | 5.94 | 6.93 | 2.20 | 7.61 | | Chloride of Calcium | ... | ... | } ... | ... | | Magnesium | } ... | 0.10 | } ... | ... | | Sodium | } 1.66 | } 0.94 | } 0.14 | 0.16 | | Potassium | } | } | } | | | Sulphate of Soda | } ... | 0.31 | } ... | ... | | Magnesia | } ... | 1.18 | } ... | ... | | Lime | trace | 1.10 | trace | trace | | Carbonate of Magnesia | 2.60 | 0.31 | trace | 0.29 | | Lime | 3.59 | 8.18 | trace | 0.46 | | Potash and Soda | 0.18 | 0.47 | trace | 0.17 | | Magnesia | 1.69 | 2.60 | trace | 0.26 | | Lime | 0.39 | 0.68 | trace | 0.14 | | Peroxide of Iron | } 6.63 | 5.05 | 0.08 | 1.17 | | Alumina | } | 8.18 | 0.39 | 0.41 | | Phosphate of Iron | 0.58 | 1.04 | trace | 0.28 | | Silica | ...