Page:The Formation of Vegetable Mould through the Action of Worms (1881).djvu/285

 as in the tropics, the castings appear, as might have been expected, to he washed down in a greater degree than in England. Mr. Scott informs me that near Calcutta the tall columnar castings (previously described), the diameter of which is usually between 1 and 1½ inch, subside on a level surface, after heavy rain, into almost circular, thin, flat discs, between 3 and 4 and sometimes 5 inches in diameter. Three fresh castings, which had been ejected in the Botanic Gardens "on a slightly inclined, grass-covered, artificial bank of loamy clay," were carefully measured, and had a mean height of 2.17, and a mean diameter of 1.43 inches; these after heavy rain, formed elongated patches of earth, with a mean length in the direction of the slope of 5.83 inches. As the earth had spread very little up the slope, a large part, judging from the original diameter of these castings, must have flowed bodily downwards about 4 inches. Moreover some of the finest earth of which they were composed must have been washed completely away to a still greater distance. In drier sites near Calcutta, a species of worm ejects