water-carried sewage this is not to be wondered at, since the value of the manure contained in one ton of Boston's sewage, for instance, is estimated to be but one cent.

An exception must be made, however, in the case of the Liernur system. It is reported of the manufacture of poudrette from a portion of St. Petersburg's sewage (collected by the Liernur system) that "it is a groundless assertion that the manufacture of poudrette does not cover the costs." It is possible that the force of this statement should be modified by accenting the word "manufacture." But the official reports of the city of Amsterdam (where the Liernur system is used) state that "the value of the dust-manure made from the sewage covers the whole working expense of the system and leaves a considerable margin besides." (Report of Charles Jonas, United States consul-general in 1894.) This is undoubtedly accounted for by the fact that fæces only are collected unmixed with water or unmanurial matter. As stated before, this system does not fully meet the sanitary requirements and is not adapted to this country, accustomed as we are to the abundant use of water and to modern conveniences.

The sewage of several of our Western cities situated in the "desert" region is disposed of for irrigation at a considerable profit. Los Angeles, Cal., received in 1895 a net revenue therefrom, above all salaries and repairs, of $1140, and in 1896 of $943.30, and in 1900 of about $3500. Pasadena, Cal., in 1905 raised $2389.22 worth of hay on 157 acres, $6900.35 worth of walnuts on 117 acres, and received $1293.52 from other products, or a total of $10,583.09; the cost of maintenance being $7958.82. The total cost of farm (460 acres) and implements was about $90,000. Altoona, Pa., received in 1898 $100 rental for their sewage farm; and in 1905 $350 for the privilege of farming 12 acres of farm and 64 acres of filter-beds. In general, few, if any, farms in districts where

irrigation is not necessary, and on which sewage must be turned in rainy as well as in dry weather, will bring any considerable rental; and no other system of treatment is known which will return any net profit above running expenses. This being the case, the endeavor should be to find for each place that method of disposal which, under the existing conditions of location, character of sewage, etc., will best meet the requirements both of the State laws and of the laws of sanitary science, and which will be least expensive, both first cost and maintenance being considered.

ART. 10. PRINCIPLES INVOLVED.

For an exposition of the principles involved we must call upon chemistry, biology, bacteriology, medicine, and kindred sciences. Their teachings, stated generally, are:

That matter in a state of putrescence is harmful to human life if taken into the system.

That volatile emanations from such matter when breathed into the lungs lower the tone of the constitution and render it more susceptible to, if they do not indeed directly occasion, disease.

That many diseases may be contracted by taking into the stomach certain germs which are found to be excreted by those already sick of such a disease, and these germs will exist for days in sewage having any amount of dilution.

That ordinarily sewage does not putresce until from twenty-four to sixty hours after its discharge, or even longer under certain circumstances, such as absence of moisture.

That the only true destruction of the dangerous characteristics of sewage is that effected by oxidation and by removal of the disease-germs.

That oxidation does not destroy but merely transforms

the putrescible organic matter into harmless mineral compounds.

The legal principles involved vary in different localities and with different interpreters of the law, frequently depending upon the ruling as to what creates a nuisance. 'I should include under this head any matter, whether solid, liquid, or gaseous, which is itself injurious to health or which may become so in contact with other substances, whether the latter may be in themselves hurtful or not; further, any matter which, though not demonstrably poisonous, is offensive to the senses." (Slater, "Sewage Treatment, Purification, and Utilization.") Such disposition of any matter that it may, while in the condition above described, approach within effective distance of any dwelling or occupied land should be held to be a nuisance. A recent ruling in the United States has included in the "creating of a nuisance" the rendering unfit for drinking purposes water which would otherwise be used thus. Under properly prepared State laws, interference with the health and rights of others should be preventable by injunction, or, in the case of injury to manufacturing interests, should subject the city to forfeiture of damages. An interesting case under the latter head is that decided in 1898 against New York City, and in favor of an oysterman whose beds were destroyed by the discharge from a near-by sewer outlet, and who was awarded their value in damages. (See Engineering Record, vol. XXXVIII. page 1.) In 1900 the New York Supreme Court decided that an injunction could be obtained restraining a city from so polluting a stream as to injure land or stock, but that damages could not be collected from a municipal corporation, although they could be from a private one. The Supreme Court of Connecticut stated in a recent ruling: "The discharge of sewage and other noxious matters into an inland stream to the injury of a riparian proprietor below has been held to be an unlawful

invasion of the rights of said proprietor, remediable by injunction, by the courts of nearly every State, by the federal courts, and by the courts of England." (Morgan et al. vs. City of Danbury, Conn.) In 1898 the California Superior Court granted an injunction against the city of Santa Rosa from emptying into a creek impure effluent from sewage irrigation. The Indiana Supreme Court, in 1900, decided that a municipality could not be enjoined from discharging sewage into any stream. In the same year the Virginia Supreme Court decided that neither municipal nor private corporations can pollute a stream by sewage or otherwise without being liable for damages for any injury caused. (See Appendix II.)

In a few States sewerage systems must be so designed, before meeting the approval of the State Boards of Health (which is by law made a necessary prerequisite to construction), as to permit and provide for a treatment of the house sewage at some future time, even if they are allowed temporarily to discharge into adjacent streams. It is probable that before very many years this will be the regulation in most States. But, in any event, where the discharge is into a stream or lake the possibility of the necessity arising in the future for treatment of the sewage should be foreseen and provided for in the design of the system. It is advisable both to consult the State Board of Health and to obtain reliable legal advice before deciding finally the question of disposal.

With these principles in mind a thorough and intelligent study of the local conditions should be made to decide how the requirements of sanitation and of law may best be met; whether any treatment of the sewage will be necessary, and if so which is best adapted to the given conditions.

ART. 11. POLLUTION OF STREAMS AND TIDAL WATERS.

The simplest solution of the problem, where it is permissible, and the one most frequently employed in this country, is to discharge the sewage directly into some flowing stream or large body of fresh water, the ocean or one of its estuaries. This is called " disposal by dilution." So far as cheapness is concerned this stands easily first among the methods of disposal, since it requires the purchase of no land and needs no care to regulate its working, excepting where the discharge is into tidal waters, when some expense is frequently gone to, both of first cost and of maintenance, to regulate the time of discharge. It is usually efficient also in removing the sewage beyond the limits of the area contributing to its volume. Looked at in a less selfish way, and considering the good of the State and country as well as of the locality sewered, other and adverse arguments present themselves. Although the sewage is removed to a distance from the contributing territory by tides or currents, it may be deposited in proximity to other communities, on banks or shores or retained by dams, thus creating a nuisance; or may render unfit for drinking, household, or manufacturing purposes water which would otherwise be so used.

The effects of sewage pollution of a stream in creating a nuisance are well illustrated by the Passaic River.

"The great extent of the pollution of the lower Passaic may be illustrated in several ways. It is apparent to the eye in the condition of the river during the summer; in the foulness of the shores where sewage-laden mud, when exposed to the sun, gives out foul odors; and it is demonstrated by every practical test. The cities of Newark and Jersey City have been compelled to seek water-supplies elsewhere at large expense, and the immediate decrease in zymotic disease in these places which has followed the change has shown how neces