or even more, and any earth except chalk or sand will answer the purpose. It may be thrown by hand, or by a self-acting apparatus moved by the weight of the person, or by the door of the closet, or by a pull-up apparatus similar to that ordinarily used in water-closets. It will be seen at once that with this system there is not only something to be taken away, but something to be brought into the towns and into the houses--the dried earth; and this constitutes a very serious objection. However, it is an objection that might perhaps be waived, if the system could be satisfactorily worked on a large scale and by careless persons, for it is essential, in a large town at any rate, that a system for the removal of refuse matters must be used which can be worked by the most careless persons. When we consider that, if the supply of earth were to fail for a day, a serious nuisance would be caused in every house; that if a servant throws a pail of slops into the earth-closet it becomes a cesspool; that the apparatus may get out of order, so that earth is not thrown in even though the hopper be full; and that an enormous quantity of earth would be required in every large town, we shall see that, at any rate for large towns, it is impracticable; and when added to this, we find the fact that one great argument in favour of the system, the supposed value of the manure produced, is entirely fallacious, it having been shown by the Sewage Committee of the British Association, that the compost, even after passing six times through the closets, can only be regarded as a rich garden soil, and would not pay the cost of carriage even to a small distance; that in fact in the disintegration and decomposition of the organic matters that takes place in the mass, almost all the nitrogen is got rid of in some way or another, we see that one great argument for its use in towns disappears. We must remember, too, that deodorisation is not necessarily disinfection, and, as Dr. Parkes pointed out, we do not know that the poisons-say of typhoid fever and cholera—are destroyed by being mixed with dried earth. It is even possible that they are preserved by it, and there can be no doubt that if the earth is not sufficiently dried, or if water is thrown on the mass, considerable danger would arise if the poisons of such diseases were present. While, however, the system is impracticable for large communities, it is one that has been found very useful indeed under suitable circumstances. It is useful for temporary large gatherings of people at flower shows, cattle shows, race meetings, volunteer reviews, &c., especially where there is supervision, and where persons can be told off to attend to the distribution of the earth. Earth-closets are suitable for use in villages and country houses in the open air, but they ought not, in my opinion to be placed indoors even in the country. Where the earth can be collected and dried on the spot, and the compost afterwards used upon the garden, the plan has been found very useful if only sufficient care be exercised, and no nuisance need be produced. To sum up with regard to the conservancy plans, their very name condemns them one and all, for use in large towns at any rate, or in the interior of houses. One of the most important of sanitary principles is, that the refuse matters should be removed as speedily and as continuously as possible from the neighbourhood of habitations, and the principle of all conservancy systems is that the refuse matters are to be kept in and about the house, at any rate as long as they are not a nuisance, which of course means that, in a large number of cases, they become a serious nuisance. It is also obvious that the carriage of the refuse matters entails considerable cost under any of these systems, and so the less frequently they are removed the less does it cost, and what is detrimental to the life of the population becomes advantageous to the ratepayers. If the manure so collected were valuable, it might, of course, be made to pay the cost of collecting, but this is not the case as a rule, the only instance in which any of these systems have been made to pay being where the excretal matters have been collected in pails or tubs, unmixed with anything which would lessen their value. With all these systems, too, it is necessary to have some method for disposing of the slops and foul water generally, which cannot be allowed to run into the water-courses, as it would contaminate them, and so it is necessary to have sewers, the construction of which will be described in the next chapter. As opposed to the conservancy systems, we have the water-carriage system, by means of which the refuse excretal matters are conveyed away in the foul water by gravitation through the sewers, and are thus removed from the houses as speedily and cheaply as possible by means of the pipes, which must in any case be provided in towns, to get rid of the foul water. The sewage is increased in bulk, but is not rendered perceptibly fouler by this admixture. Indeed, as a rule, the sewage of a town supplied with water-closets is less foul than that of a town supplied with middens. Although, however, sewers are necessary in towns to carry the foul water away, in country places the slop water may be allowed to run into the surface drains, provided they do not pass near wells, and this is best managed by means of a contrivance which I shall describe in the next chapter. The water-carriage system has disadvantages of its own, and requires special precautions to be taken, which so far as they are connected with dwelling-houses, will be described in the next two chapters. CHAPTER V. SEWERAGE-MAIN SEWERS AND HOUSE BRANCHES, TRAPS, EVEN where conservancy systems are used for the removal |