Chat Moss is an immense peat-bog of about twelve square miles in extent. Unlike the bogs or swamps of Cambridge and Lincolnshire, which consist principally of soft mud or silt, this bog is a vast mass of spongy vegetable pulp, the result of the growth and decay of ages. Spagni, or bog-mosses, cover the entire area; one year's growth rising over another, the older growths not entirely decaying, but remaining partially preserved by the antiseptic properties peculiar to peat. Hence the remarkable fact that, though a semifluid mass, the surface of Chat Moss rises above the level of the surrounding country. Like a turtle's back, it declines from the summit in every direction, having from thirty to forty feet gradual slope to the solid land on all sides. From the remains of trees, chiefly alder and birch, which have been dug out of it, and which must have previously flourished on the surface of the soil now deeply submerged, it is probable that the sand and clay base on which the bog rests is saucer-shaped, and so retains the entire mass in position. In rainy weather, such is its capacity for water that it sensibly swells, and rises in those parts where the moss is the deepest. This occurs through the capillary attraction of the fibres of the submerged moss, which is from twenty to thirty feet in depth, while the growing plants effectually check evaporation from the surface. This peculiar character of the Moss has presented an insuperable difficulty in the way of draining on any extensive system--such as by sinking shafts in its substance, and pumping up the water by steam-power, as has been proposed by some engineers. For, supposing a shaft of thirty feet deep to be sunk, it has been calculated that this would only be effectual for draining a circle of about one hundred yards, the water running down an incline of about 5 to 1; indeed, it was found, in the course of draining the bog, that a ditch three feet deep only served to drain a space of less than five yards on either side, and two ditches of this depth, ten feet apart, left a portion of the Moss between them scarcely affected by the drains.