=The Dry-earth System= is an important modification of the pail system. In it dry earth or some other material is added to the excreta, thus converting them immediately into an inodorous mass. Probably the best contrivances for thus deodorising the excreta, as soon as they fall into the receptacle, are =Moule’s or Moser’s Earth-Closets=. It is found that 1½ lbs. of dry earth completely deodorise the closet each time it is used. Loamy earth is the most valuable material; a mixture of peat and earth or ashes is very good; sand, gravel, and chalk are practically useless. It is necessary that the earth should be very dry, and that it should be finely sifted. If the earth is damp, decomposition of the excreta speedily occurs. The act of sitting and rising works a hopper which scatters a supply of earth. Charcoal and sawdust have also been used in connection with Moule’s or Moser’s closet, and with good results. Charcoal has been obtained cheaply for the purpose from street sweepings, and from seaweed, as in Stanford’s closet, in which 1∕2 lb. of charcoal from seaweed is used each time. Mr. Stanford found that while dry clay absorbs only 4 to 5 per cent. of water, dry charcoal prepared from seaweed absorbs 14·7 per cent. The best material, however, is dry earth, but it must be thoroughly dry. The microbes in the earth disintegrate the excreta, converting them into mineral compounds, such as nitrates. Even the paper used disappears. Hence the same earth may be used over again after being stored dry for six weeks. Whether the excreta of an infectious patient are freed from infection by this process is doubtful; if not, the infection might be scattered by means of dust. The dry earth system is more expensive in use than the pail system, and although applicable to villages and isolated houses, is quite unsuited to large towns, owing to the practical difficulties connected with the procuring and storing of dry earth. The dry earth closet requires frequent attention, in addition to not being so convenient as the pail closet; and there is much less manurial value in the contents of earth closets than in those of pail closets. The advantages of the earth-closet as compared with the water-closet have been thus summarised by the late Sir Geo. Buchanan. “It is cheaper in the original cost, it is not injured by frost, it is not damaged by improper substances driven down it, and it very greatly diminishes the quantity of water required by each household.” These advantages only accrue when the system is perfectly worked, and do not counterbalance the immense advantage and greater safety of the water-carriage system in towns.