1283. Night-soil, it is well known, is a very powerful manure, and very liable to decompose. It differs in composition; but always abounds in substances composed of carbon, hydrogen, azote, and oxygen. From the analysis of Berzelius, it appears that a part of it is always soluble in water; and in whatever state it is used, whether recent or fermented, it supplies abundance of food to plants. The disagreeable smell of night-soil may be destroyed by mixing it with quicklime; and if exposed to the atmosphere in thin layers, strewed over with quicklime in fine weather, it speedily dries, and is easily pulverised for mixing with the earth. The Chinese, who have more practical knowledge of the use and application of manures than any other people existing, mix their night-soil with one third of its weight of fat marl, make it into cakes, and dry it by exposure to the sun. These cakes, we are informed by the French missionaries, have no disagreeable smell, and form a common article of commerce of the empire. The earth, by its absorbent powers, probably prevents, to a certain extent, the action of moisture upon the dung, and likewise defends it from the effects of air. Desiccated night-soil, in a state of powder, forms an article of internal commerce in France, and is known under the name of poudrette; in London it is mixed with charcoal or quicklime, and sold in cakes under the name of 'desiccated night-soil.' The latter is, however, an objectionable process, because the lime expels a large portion of the ammonia which the night-soil contains.
