2011. Dutch forcing-pits are of various kinds, all characterised by the most economical application of material, conservation of heat, and saving of labour. The leading features of these pits are the substitution of dung for fire-heat, and the complete covering of the sides of the pit, up to the edge, with dung or litter. The coverings put over the glass during night are also much thicker than those in general use in this country. The plants are kept very close to the glass; and the glass is in very large panes, with very slight astragals. The great object is to prevent the escape of heat, and at the same time to admit all the light possible. All the details of the mode of constructing and managing these pits will be found in the Gardener's Magazine, vol. iii. p. 385.