system to be adopted. In many cases financial limitations will be forced upon the engineer as an unfortunate but imperative argument in the choice not only of the details of the system but even of the system itself. He must perforce recognize these limitations in addition to the requirements of sanitation and convenience, but should not carelessly assume that since there is but little money to spend upon the work the care given to the design will need to be only proportionately great. He should realize that the highest talent is needed to obtain the best results with limited resources.

The solution of the difficulty when a complete watercarriage system is rendered out of the question by reason of its cost may lie in the construction of only the most necessary portion of the system or in the adoption of one of the dry-sewage systems.

ART. 2. DRY SEWAGE METHODS.

The methods in common use for removing excrement and liquid wastes may be conveniently divided into three general classes: (1) Dry Sewage, (2) Pneumatic, and (3) Water-carriage systems.

The most primitive method of application of excrements. to the soil-if it can be called a method-would be embraced under the first head. The old-fashioned privy was a step forward, and in a large part of this country is as yet the only one which has been taken, privacy being the main argument for its adoption. But, while contributing somewhat to this and to comfort, it cannot be considered as a sanitary appli"Constructed for the avowed purpose of retaining the solid matters as long as possible upon the premises, they become centres of pollution and infection. The liquid portions, escaping, pollute the soil and neighboring wells; the noxious exhalations arising from their putrefying contents

ance.

contaminate the air." (Samuel M. Gray's Report on Proposed Sewerage System for Providence, R. I.)

Regular movement of the bowels is essential to health and to bodily and mental vigor. Yet a rainy day, a deep snow, or publicity of location has kept many a person from the daily attention to nature's demands when this requires a visit to the outdoor privy.

This last objection is met by the indoor closet connected with a cesspool; but there is probably no subject upon which sanitarians are more thoroughly agreed than upon the inherent vileness and danger of the cesspool as ordinarily constructed. Fresh sewage if not taken into the stomach is neither injurious to health nor very offensive to the smell; but from putrescent excreta and kitchen slops come those noisome gases which, if not themselves bearers of malefic germs, at least lower the vitality and render the body more vulnerable to disease. Retained for weeks and months in a liquid or semi-liquid state in a cesspool, sewage is then under the conditions best adapted to putrefaction in its foulest form. And in very few, if any, cases is the plumbing of the house adapted to exclude from the air of the dwelling the gases emitted; indeed it is doubtful if this can be accomplished with certainty when, as is too often the case, the cesspool is tightly covered or sealed with snow or ice. Moreover, practically no cesspools are water-tight, though many are thought to be so. A cesspool 8 feet in diameter and 10 feet deep to which a family of five contribute a daily average of 25 gallons of sewage (a low estimate) would, if tight, require to be cleaned twice each year. Very few, it is believed, are cleaned this often; many are never cleaned, but the contained liquid leaches out into and through the adjacent soil, which soon loses its power to purify it.

This vilest of liquids is dangerous in two ways: it may reach and taint wells for hundreds of feet around, and it may

pollute the air existing in the soil under cellars, which air will exhale and permeate the houses above. In excavating for sewers in gravelly soil in a city street the author has found the gravel colored black by the liquid from a cesspool located 75 feet distant in the rear of the house opposite; which liquid must consequently have passed under or around the cellar of this house.

It seems advisable to speak thus at length on this subject for the reason that many intelligent persons look with favor on the cesspool as a sanitary contrivance, whereas in most cases it is one of the greatest abominations permitted in any civilized community. (See note, page 13.)

ART. 3. DRY SEWAGE SYSTEMS.

The methods already referred to can hardly be called systems, but are rather makeshifts. The simplest systems which can be at all commended are the Pail system and the Earth-closet. These are used but little in this country, but would be for many small villages a vast improvement over the privy or cesspool.

The Pail system consists essentially of the placing under the privy-seats of pails, which are to be removed, emptied in some spot where a nuisance will not thereby be created, cleaned, and returned. Duplicate pails must be provided to be used in place of these during their absence.

This method is in use at Marseilles, Havre, and other French cities; at Rochdale, Birmingham, Manchester, and other places in England; but only in certain districts of these cities, which are introducing water carriage and are yearly increasing the territory thus sewered. It has been used by a few communities in this country also, among them Vineland, N. J., Memphis, Tenn., Atlanta, Ga., and Warren, O., but is being replaced in these with water-carriage systems.

A modification of and improvement upon the Pail system is the Earth-closet system, in which pulverized dry earth, charcoal, or ashes are used as a deodorizer and are applied to the excreta while fresh, the mixture being subsequently removed, preferably as in the Pail system. Brick-clay and loam rank high as deodorizers when applied in a perfectly dry and powdered state. Ashes are not so effective. In Bremen powdered turf is used. There is not evident à suffia cient superiority in charcoal to compensate for its cost and other disadvantages.

The deodorizing-powder should be applied each time the closet is used. An excellent arrangement is that of a large box or barrel resting upon an extension of the seat and with an aperture and slide so contrived that any desired amount of the powder may be deposited upon the excrement by a

21"

18

18

FIG. 1.-MODIFIED BIRMINGHAM PAIL.

slight motion of a convenient handle. The simplest method of applying the deodorizer is by a small scoop or shovel, the earth being kept in a box placed in a convenient position in the closet.

For either the Pail or Earth-closet system the receptacle should be round, as this form is more easily cleaned than a square one; and preferably of metal, as a wooden pail soon

becomes saturated with foul liquors. A good form is that of the modified Birmingham pail. The pails should be thoroughly cleaned after each emptying. If the earth closet is used a thin layer of earth should be spread over the bottom of the pail when it is replaced under the seat.

The mixture of earth and excreta may be dried and used again; but there is a possible danger in this, since bacteria are not often destroyed by moderate heat; it will probably be found more convenient also to deposit it immediately upon the garden or field as a fertilizer. If the Pail or Dry-earth system is adopted for a village or city an arrangement may be made by contract for removing the buckets or tubs at intervals of not more than a week, the material to be disposed of by the contractor. Such disposition of it should be made -either by placing it directly upon the fields; or by drying and pulverizing it, in which form (poudrette) it is more convenient for use as a fertilizer; or by burning it (see Chapter II)—as will avoid the creating of a nuisance (see Art. 10).

There are several methods, some patented, for disposing of dry sewage and garbage on the premises by means of heat, by either drying or cremating. The heat for these is obtained either from a furnace constantly burning, in which case its use in summer is exceedingly inconvenient and is usually dispensed with; or by occasional fires lighted at long intervals, during which the waste matter undergoes dangerous putrefaction. On account of these and other equally serious objections these methods are not to be commended, particularly since the cost, were every house to adopt them, would in most locations suffice to construct an excellent watercarriage system.

These dry-sewage systems, though improvements on the privy and cesspool, are imperfect from a sanitary point of view in that they require the excreta to be stored about the premises for a certain period, and because they fail to pro