_Improving the Soil by Paring and Burning._--It has long been familiarly known, that a decided improvement has been produced on some soils by burning. Its advantages have chiefly been observed on two sorts, heavy clays and peat soils, on both of which it has been practised to a great extent. The action of heat on the heavy clays appears to be of a twofold character, depending partly on the change effected in its physical properties, and partly on a chemical decomposition produced by the heat. The operation of burning is effected by mixing the clay with brushwood and vegetable refuse, and allowing it to smoulder in small heaps for some time. It is a process of some nicety, and its success is greatly dependent on the care which has been taken to keep the temperature as low as possible during the whole course of the burning. Experience has shown that burning is by no means equally advantageous to all clays, but is most beneficial on those containing a considerable quantity of calcareous matter, and of silicates of potash. In such clays heat operates by causing the lime to decompose the alkaline silicates, and liberate a quantity of the potash which was previously in an unavailable state. Its effect may be best illustrated by the following analyses by Dr. Voelcker of a soil, and the red ash produced in burning it. Soil. Red Ash. Water 0.93 1.18 Organic matter 10.67 3.32 Oxides of iron and alumina 13.40 18.42 Carbonate of lime 23.90 8.83 Sulphate of lime trace 1.15 Carbonate of magnesia 1.10 " Magnesia " 1.76 Phosphoric acid trace 0.71 Potash 0.38 1.08 Soda 0.13 " Chloride of sodium " 1.03 Insoluble matter, chiefly clay 49.66 62.52 ----- ----- 100.17 100.00