houses. The accompanying diagrams, (Figs. 48-49,) illus trate the difference between the old system of drainage with brick sewers under the streets, and brick drains under the houses, and pipe sewers under main streets and through the back yards of premises. A measurement of these two

Fig. 48.-OLD STYLE HOUSE DRAINAGE AND SEWERAGE.

methods will show that the lengths of the drains in the new system, are to those of the old, as 1 to 24;-the fall of the house drains, (these having much less length,) would be 10 times more in the one case than in the other;-the main sewers would have twice the fall, their area would be only, and their cubic contents only

Experience in England has shown that if the whole cost of water supply and pipe sewers is, with its interest, divided over a period of thirty years, so that at the end of that time it should all be repaid,-the annual charge would not be greater than the cost of keeping house-drains and cess

pools clean. The General Board of Health state that "the expense of cleansing the brick house-drains and cess-pools for four or five years, would pay the expense of properly constructed water-closets and pipe-drains, for the greater number of old premises."

One of the reports of this body, which has added more than any other organization to the world's knowledge on these subjects, closes with the following:

"Conclusions obtained as to house drainage, and the sewerage and cleansing of the sites of towns."

"That no population living amidst impurities, arising "from the putrid emanations from cess-pools, drains and 66 sewers of deposit, can be healthy or free from the attacks "of devastating epidemics.

"That as a primary condition of salubrity, no ordure

"and town refuse can be permitted to remain beneath of 65 near habitations.

"That by no means can remedial operations be so con"veniently, economically, inoffensively, and quickly effected "as by the removal of all such refuse dissolved or sus"pended in water.

"That it has been subsequently proved by the operation "of draining houses with tubular drains, in upwards of "19,000 cases, and by the trial of more than 200 miles of "pipe sewers, that the practice of constructing large brick 66 or stone sewers for general town drainage, which detain "matters passing into them in suspension in water, which "accumulate deposit, and which are made large enough "for men to enter them, and remove the deposit by hand "labor, without reference to the area to be drained, has "been in ignorance, neglect or perversion of the above recited principles.

"That while sewers so constructed are productive of 'great injury to the public health, by the diffusion into "houses and streets of the noxious products of the decoin"posing matters contained in them, they are wasteful from "the increased expense of their construction and repair, "and from the cost of ineffectual efforts to keep them free "from deposit.

"That the house-drains, made as they have heretofore "been, of absorbent brick or stone, besides detaining sub'stances in suspension, accumulating foul deposit, and "being so permeable as to permit the escape of the liquid ' and gaseous matters, are also false in principle and waste"ful in the expense of construction, cleansing and repair.

"That it results from the experience developed in these "inquiries, that improved tubular house-drains and sewers "of the proper sizes, inclinations, and material, detain and "accumulate no deposit, emit no offensive smells, and re"quire no additional supplies of water to keep them clear

"That the offensive smells proceeding from any works "intended for house or town drainage, indicate the fact "of the detention and decomposition of ordure, and afford "decisive evidence of mal-construction or of ignorant or defective arrangement.

"That the method of removing refuse in suspension in "water by properly combined works, is much better than "that of collecting it in pits or cess-pools near or under"neath houses, emptying it by hand labor, and removing "it by carts.

66

"That it is important for the sake of economy, as well as for the health of the population, that the practice of "the removal of refuse in suspension in water, and by com. "bined works, should be applied to all houses, especially those occupied by the poorer classes."

Later investigations of the subject have established two general conclusions applicable to the subject, namely, that: "In towns all offensive smells from the decomposition "of animal and vegetable matter, indicate the generation "and presence of the causes of insalubrity and of prevent"able disease, at the same time that they prove defective "local administration;

"and correlatively, that:

"In rural districts all continuous offensive smells from "animal and vegetable decomposition, indicate prevent"able loss of fertilizing matter, loss of money, and bad "husbandry."

The principles herein set forth, whether relating to sanitary improvement, to convenience and decency of living, or to the use of waste matters of houses in agricultural improvement, are no less applicable in America than elsewhere; and the more general adoption of improved house drainage and sewerage, and of the use of sewage matters in agriculture, would add to the health and prosperity of its people, al would indicate a great advance in civilization.

NOTE TO CHAPTER XI.-(SECOND EDITION.)

On reading over the preceding chapter, I am disposed to leave it essentially as first written, because the principles which it sets forth are as true now as they were then, and because there has been no essential modification in processes which makes it important to change its directions.

I would say, however, that the system of Back Drainage described, has not come into general use, for the reason that it is considered better, all things taken into the account, to avoid, so far as possible, the laying of public drains on private land. Where there are lanes between the backs of the houses, or where it is practicable to take a small strip of land for this purpose and put it under the control of the public authorities, the manifest advantages of the system may be availed of. In the majority of instances, however, this will not be practicable.

So far as the use of small pipes is concerned, experience has fully justified all that was anticipated ten years ago. Especially where the question of stormwater can be left out of the account, that is, where this can be allowed to run through surface gutters, or where separate sewers can be made for its removal. What is known as the Separate System, that is, the removal of house-drainage by itself, is much to be recommended, and even in cities where house-drainage alone is to be accommodated, very small pipes, even six or eight inches in diameter, may be very largely used for lateral sewers.

The use of small pipes is greatly facilitated, and their permanent working secured, by the adoption of Roger Field's method of accumulating the drainage of a few houses at the upper end of each line, including the roofwater, in underground tanks of considerable size, which, by the automatic action of an ingeniously arranged siphon, discharge their whole contents with great rapid