George Thudichum, with a filter bed consisting of 3 feet in depth of coke, broken to small fragments. In 1891 Sidney Lowcock constructed a novel sewage purification plant for a private residence at Ashstead, England, in which he embodied, probably for the first time, the principle that the bacterial treatment of sewage involved two distinct stages: the breaking down of the solid organic matter, or liquefaction, followed by nitrification. For the first stage he employed a closed tank, filled with broken stone. The sewage rose upward through this tank, then passed down through a series of nine perforated trays, each containing a thin bed of coke. The object of so many trays was to secure a more minute subdivision of bacterial labor.

It is too early to say what rate of filtration will prove feasible with bacteria beds, but it seems doubtful whether the 500,000 to 1,000,000 gallons or more per acre, claimed in England, can be practical for a series of years without either poor results or large outlays for replacing clogged filtering material.

THE SEPTIC TANK is designed to provide the first stage of bacterial action, mentioned just above, without the intervention of filtering material. The sewage first enters a small grit chamber, where sand and like heavy matter is speedily deposited on account of its relatively great weight. The sewage then goes on to a narrow and rather long and shallow tank, having a trapped inlet and outlet, the better to exclude the air. The bulk of the suspended organic matter is deposited and retained in this tank. The anaerobic bacteria seize upon and break up the sludge, which is transformed into dissolved and gaseous matter. The former passes out with the tank effluent. As any sludge left behind remains in the tank week after week, there is no lack of opportunity for complete bacterial reduction. The sludge accumulates by slow degrees. The tank effluent, as has been stated, is about as well purified as that from chemical precipitation tanks, but it is in far better condition for further treatment, while the sludge problem has been practically eliminated. Where further treatment is required to prevent water pollution the tank effluent is generally passed through bacteria beds, sometimes being preceded by aëration in order to establish more favorable conditions for the aërobic bacteria.

The septic tank system was put in use at Exeter, England, in August, 1896, by Mr. Donald Cameron, town surveyor. Since then many other septic tanks have been built. The Exeter tank, like others built under Mr. Cameron's patents, was tightly covered to exclude air and light. Covering, however, does not seem necessary.

It is asserted that the septic tank was developed independently at Urbana, Ill., in 1894, by Professor A. N. Talbot. Certainly he built a tank there and then, which acted in much the same way as the septic tank. In 1895 he designed a more pretentious one for Champaign, Ill., which was built in 1897. See Metcalf, "Antecedents of the Septic Tank," Proceedings of the American Society of Civil Engineers (New York, 1901). MANUFACTURING WASTES may generally be discharged into town sewers. Occasionally they are of such a character as to demand separate treatment. Or the conditions may be such that proper treatment will result in the recovery of some product of commercial value. Much information

on the subject will be found in the reports of the Massachusetts State Board of Health. HOUSES NOT CONNECTED WITH SEWERS. Although, as now understood, sewage is limited to those household and industrial wastes which are removed by sewers, it will be convenient to consider, in addition, the disposal of excrementitious matters and fouled water from such houses and other buildings as are not connected with the sewers. In rural districts this is generally a simple matter. Privy vaults, whether adjoining or more or less remote from houses, are generally little more than holes in the ground, into which the wastes fall and where they remain until removed at frequent intervals. The occasional addition of small quantities of dry earth or ashes will do much to lessen the almost inevitable nuisances of these devices. The comfort and ease of the family demand that such conveniences be placed as near the living rooms as possible, and preferably under the same roof; while in densely populated districts the latter is imperative. Wherever decency and a due regard for health prevail this leads to the adoption of some portable receptacle, which can be kept in a sanitary condition. The two chief means employed to meet this demand are the earth-closet and the pail system. The former is said to have been invented in 1858, by the Rev. Henry Moule, Vicar of Fordington, England. He utilized the deodorizing powers of common soil and devised a mechanism for automatically dumping some of it into the closet when needed, somewhat on the same principle as the flushing arrangement for a water-closet. In the earth-closet a bucket, or some larger receptacle, may be used for the reception and removal of wastes. The pail system is not much different from the earth-closet, except that no earth or other deodorizer is necessarily used. The pails should be made of metal, or some other non-absorbent material. Tightfitting covers should be provided. With the introduction of the water-closet, with its flushing tank and its pipe for the removal of wastes from the houses, a new problem arose in the way of final disposal. If no cesspool had been provided for sink and bath wastes, one was built somewhere in the yard. These, also, are generally mere holes in the ground, walled up roughly to prevent the caving in of the earth, but not made water-tight. In sandy soils the liquid soaks away. The solid matters are decomposed in the manner explained in the paragraph on septic tanks. In clayey or wet soils cesspools are sure to overflow. Theoretically all cesspools should be water-tight, but practically only a very few are.

The contents of earth-closets may be utilized as fertilizing material with but little difficulty, either by composting or by direct application to the land. The utilization of pail-system wastes. is not so easy, since they contain a large percentage of moisture. An absorbent may be used to reduce the moisture, or the pails may be emptied where their contents can drain out. Still another way is to reduce the stuff to a powder in some form of drier. Occasionally night soil from the pail system, and possibly from privies, is burned in garbage furnaces, care being taken to mix it with the driest material available. One of the best means of disposing of all night soil and allied matter is to bury it in trenches.

BIBLIOGRAPHY. Rafter and Baker, Sewage Disposal in the United States (New York, 1893),

SEWAGE.

an exhaustive discussion of both principles and methods; Waring, Modern Methods of Sewage Disposal (New York, 1894), a popular review of principles and methods; Kiersted, Sewage Disposal (New York, 1894), a brief discussion with particular reference to disposal by dilution; Baker, Sewerage and Sewage Purification (New York, 1896), brief and popular; Rideal, Sewage and the Bacterial Purification of Sewage (New York, 1900), a pretty thorough and rather scientific discussion of the bacterial phases of sewage treatment, written by an Englishman and almost wholly from the English point of view; Dibdin, Purification of Sewage and Water (London, 1903), also relates chiefly to the bacterial aspects, almost wholly English, but less technical than Rideal; Thudicum, The Bacterial Treatment of Sewage (London, 1900), a brief, popular review of recent bacterial studies and results; Barwise, The Purification of Sewage (New York, 1899), another English author, fairly popular in style and more general in range than the three preceding; Crimp, Sewage Disposal Works (2d ed., London, 1894), the standard English engineering treatise, including principles, methods, and descriptions of works, but has nothing on the recent bacterial studies; Corfield, The Treatment and Utilization of Sewage (3d ed., London and New York, 1887), somewhat similar to but less comprehensive than Crimp; Slater, Sewage Treatment, Purification, and Utilization (London, 1888), brief, semi-popular, controversial, and not up-to-date, but valuable on account of a descriptive chronological list of 456 English patents on methods of treating sewage, issued from 1846 to 1886, inclusive; Bailey-Denton, Sewage Purification Brought Up to Date, 1896 (London and New York, 1896), by one of the chief exponents of intermittent filtration, written after the earlier announcements of the more recent bacterial studies, and describing eight land-filtration systems; Tidy, The Treatment of Sewage (New York, 1887), brief, comprehensive, semi-technical; Burns, Utilization of Town Sewage, Irrigation, and Reclamation of Waste Land, being vol. v. of Outlines of Modern Farming (6th ed., London, 1889), a semipopular discussion of sewage farming, from the agricultural point of view, a number of years back; United States Consular Reports (special, vol. xvii.), Disposal of Sewage and Garbage in Foreign Countries (Washington, 1899), mostly popular, and generally meagre in detail, but containing some excellent descriptive matter. See FIL TER PRESSES; FILTER AND FILTRATION, IRRIGATION; SEWERAGE AND DRAINAGE; WATER SUPPLY. SEWAGE EARTH-CLOSET. See SEWAGE. SEWAGE FARMING. The utilization of sewage in the growth of field, orchard, and garden crops. The most noted farms are at Paris, Berlin, Danzig, Breslau, and Birmingham, in Europe, and at Pullman, Ill., Los Angeles, Cal., South Framingham, Mass., and Plainfield, N. J., in the United States. Sewage farming, which is largely a development of the last third of the nineteenth century, is an attempt to combine cropgrowing with sewage purification. Where intelligently managed a high degree of purification is attained without creating a nuisance in the neighborhood, and the excellent crops which are grown may be used without menace to health in spite of popular prejudice to the contrary. Aside from

the irrigation value of the water, sewage is of some importance agriculturally on account of the fertilizing elements it contains. Analyses show that less than 2 parts in 1000 of average sewage is solid matter, and that a ton of sewage contains from 0.15 to 0.25 pound of nitrogen, from 0.045 to 0.065 pound of phosphoric acid, and from 0.025 to 0.040 pound of potash. These would have a cash value of 3% to 5 cents. Since, however, in actual operation much of the nitrogen is lost, the real value of sewage will not exceed 3 cents per ton and one to two cents per ton is more nearly its true manurial value. The recognized greater agricultural value of sewage over river water for irrigation is accountable for the 25 to 50 per cent. increase in rent per acre for land irrigated with sewage. Unless care be taken to prevent the sewage from coming in direct contact with crops intended for consumption in the raw state, the methods of applying sewage do not differ from those of irrigation (q.v.). Sewage farms are located preferably on open soils with a sandy or gravelly subsoil. Clay soils are less satisfactory.

Since experience indicates that the best crops are secured when the sewage is applied only as needed, arrangements should be made for the disposal of surplus sewage that may accumulate when the crops cannot use it. This is usually done by making separate filtration areas or by growing crops capable of withstanding large quantities of water, such as Italian rye grass, orchard grass, perennial rye grass, and blue grass. With a controllable supply of water practically all crops suitable for the climate can be grown to perfection. In Southern California orchards are very successfully irrigated with sewage. From the standpoint of sewage disposal the primary object of sewage irrigation is to purify the sewage so that it may not contaminate the underground water or streams. Experience on sewage farms, both in Europe and America, shows that every essential requirement of sewage purification is present in sewage farming, and that when sewage is rightfully used the water flowing from these farms is clear and sparkling.

Consult: United States Geological Survey Water Supply and Irrigation Papers Nos. 3 and 22 on Sewage Irrigation (1897, 1899); Rafter and Baker, Sewage Disposal in the United States (New York, 1894); Waring, Modern Methods of Sewage Disposal (ib., 1894); Kiersted, Sewage Disposal (ib., 1894); Birmingham Sewage Inquiry Report, 1871.

SEWALL, sū'al, MAY (WRIGHT) (1844—). An American educator, lecturer, and author, born in Milwaukee, Wis. She graduated at Northwestern University in 1866, and in 1880 married Theodore L. Sewall, who died in 1895. She was for many years prominently identified with the woman's suffrage movement and with the education of women, was member and officer of many women's clubs and delegate to numerous women's congresses, both in the United States and abroad. She was one of the lady managers of the Columbian Exposition at Chicago in 1893, and in 1900 she was appointed a commissioner to the Paris Exposition. For a long time she was principal of a girls' classical school in Indianapolis, Ind., founded by her husband. She wrote several works on woman suffrage and kindred topics, and edited The Historical Résumé of the World's Congress of Representative Women.

SEWARD.

reëlected. For several years after the expiration of the term he gave his whole time to the practice of his profession, at Auburn, and appeared as counsel in a number of important criminal cases. In 1849 he was elected to the United States Senate, and at once took a prominent place among the leaders of the Whig Party and became the most intimate Senatorial counselor of President Taylor. In the debate on the Compromise Measures of 1850 (q.v.) he delivered, on March 11th of that year, an able speech in which he vigorously denounced slavery, and startled the opposition by declaring that "there is a higher law than the Constitution." He supported the French Spoliation Bill and a protective tariff, spoke on the American fisheries, the Texas debt, the Hungarian Revolution, and other subjects, and vigorously opposed the Kansas-Nebraska Bill (q.v.). In 1855 he was reëlected to the Senate, in spite of the opposition of KnowNothings and Whigs of Southern sympathies. He was an influential factor in the organization of the Republican Party, and for the first few years was generally regarded throughout the Union as preeminently its leader. In October, 1858, he made a notable speech at Rochester, in which he spoke of the antagonism between freedom and slavery as an 'irrepressible conflict,' which could only terminate by the United States becoming entirely a slave-holding nation or entirely free. Prior to the National Republican Nominating Convention at Chicago he was the most conspicuous candidate for the Republican nomination for President in 1860, and on the first ballot received 1732 votes, but was finally defeated by Abraham Lincoln. After Lincoln's election Seward became Secretary of State, and in this capacity rendered services of almost inestimable value to the nation, holding the office during the Civil War and the four years of Johnson's administration. He negotiated a large number of treaties with foreign governments and conducted the foreign relations of the United States during these critical times with remarkable tact and success. Notable instances of this were the case of the Trent affair (q.v.), the question arising out of the French intervention in Mexico, and the negotiations concerning Great Britain's obligations as a neutral nation. (See ALABAMA CLAIMS.) He also negotiated with Russia, in 1867, the treaty for the purchase of Alaska. His State papers are models of clear and vigorous style. During the war he supported President Lincoln in all his efforts to raise and equip the armies, and gave his approval to the emancipation proclamations. On the evening of April 14, 1865, the same day on which President Lincoln

was assassinated, an assassin named Paine en

tered Seward's room and inflicted dangerous wounds upon him as well as upon his son Frederick. He gradually recovered, however, and continued as Secretary of State' in the Cabinet

of President Johnson until the end of his term. He entertained moderate views of reconstruction and supported the plan of President Johnson, thus alienating from himself the more radical wing of his party. Upon his retirement from office in 1869, he made a journey to Alaska, and in the following year set out upon a tour of the world, visiting the principal countries of Europe, Asia, and Africa, and being received everywhere with great honor. He died at Auburn on October 10, 1872. His speeches and orations appeared

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in five volumes, and his official correspondence was published by order of Congress. For his life, consult: Baker, (New York, 1855); Frederick W. Seward (ib., 1877); and especially Frederick Bancroft (ib., 1900); also William H. Seward's Travels Around the World (New York, 1873), by his adopted daughter, Olive Seward. SEWEL, su'el, WILLIAM (1654-1720). Quaker historian and scholar. He was born and the Rise, Increase, and Progress of the Christian People Called Quakers, published in Dutch at Amsterdam in 1717, and in English translation (by himself) at London in 1722, is a standard work of unquestionable accuracy. Consult his Life in the edition published at New York (1844).

lived all his life in Amsterdam. His History of

SEWELL, JONATHAN (1766-1839). A Canadian jurist, son of Jonathan Sewall (1728-96). He was born in Massachusetts, was educated in England, and in 1785 went to New Brunswick and studied law. He was appointed SolicitorGeneral in 1793, Attorney-General in 1795, and from 1808 till 1838 was Chief Justice of Lower Canada. He published a Plan for a General Federal Union of the British Provinces in North America (1815), and is sometimes credited with having been the first to propose Canadian federation.

SEWELL, MARY (1797-1884). An English authoress, daughter of a gentleman farmer named Wright. In 1819 she married Isaac Sewell, a banker. She wrote verses for children and young people, which had an enormous sale. Homely Ballads (1858) reached the fortieth thousand, Mother's Last Words (1860) passed beyond a million copies, and Our Father's Care (1861) exceeded three-quarters of a million. Besides these and other poems she wrote Patience Hart's Experiences in Service (1862), and other popular short tales. All her work was simple in style and ethical in theme. Consult Poems and Ballads, edited with memoir by Mrs. Bayly (London, 1886).

robe made of sewellel hide, the animal itself being called o-gwool-lal in Chinook, squallal in Yakima, and showt'l in Nisqually), or MOUNTAIN BEAVER, A curious little beaver-like rodent (Haplodon nia to British Columbia, which lives in wet places. rufus) of the mountains from northern Califorovergrown with vegetation, where it makes extensive burrows and runways often kept wet by running water. They usually live in colonies, and hibernate, preparing for the winter by cutting and collecting great quantities of woody plants and ferns, which they carry to places near their burrows and spread out to dry thoroughly before taking them into their burrows as stored food. The Indians ate them and made much use of their soft fur. A second species (Haplodon major) has been described from California. The many structural differences from the beaver have led to placing the sewellels in a family (Haplodontidae) by themselves. They are regarded as most nearly representing the ancestral type of the squirrels.

SEWELLEL (Chinook Indian she-wal-lal,

SEWERAGE (OF. seuwiere, canal, from ML. exaquatorium, drainage-canal, from Lat. ex, out

aqua, water) AND DRAINAGE (from AS. drehman, dreahnian, drenian, to drain, from AS.,

Goth. dragan, to draw, OHG. tragan, Ger. tragen, to carry). The removal and disposal of liquid and water-borne solid household wastes, the freeing of towns and cities from surface water, and the lowering and removal of subsoil water.

The two fundamental principles in the design of sewerage systems are (1) the removal of sewage before offensive decomposition sets in, which may be effected by providing sewers of ample capacity, uniform and sufficient slope, and smooth interiors; and (2) the disposal of sewage in such a manner that neither water, soil, nor air will be polluted thereby. Sewerage systems are generally divided into two portions: the collecting sewers and appurtenances and the outfall sewer or sewers. In addition there may be disposal works, including either a pumping or a purification plant, or both. The aim always is so to design the collecting and outfall sewers that the discharge may be by gravity, thus avoiding the expense of a pumping plant.

Sewerage systems, as now understood, date chiefly from the middle of the nineteenth century. A few ancient cities had sewers for the removal of fouled liquids, as well as for drainage. The most notable instance of this was Rome. (See CLOACA.) But the Roman sewerage system did not serve the whole population, by any means. The drainage of London was the subject of legislation as early as 1225, but down to 1815 it was a penal offense to discharge excrement or other offensive matter into the drains of that city. In 1847 the first act was passed making it compulsory to drain London houses into the sewers, and in 1859 work was begun on a system of intercepting sewers and storage tanks to cut off the discharge of sewage into the Thames within the city.

Paris had drains prior to 1536, but in 1663 their total length is said to have been only about six miles, of which one and one-half miles were closed and the remainder open channels. In 1820 Paris made the use of cesspools obligatory, but permitted the liquid overflow to be discharged into the sewers. In 1880 a move was made to permit the discharge of all house sewage into the sewers, but up to the close of 1893, or just before the full adoption of the sewerage plan, of 266,044 houses in the city, only 10,934 were directly connected with the sewerage system.

In the United States, Boston had drains as early as 1701. After the adoption of a city charter in 1823 Boston assumed the ownership and control of all the drains and sewers which had been built by private parties. The date or which the sewers were opened for the reception of water-closet matter generally is not available; but presumably it followed shortly after the introduction of an ample public water supply, in 1848.

It may be said of all cities that a sanitary sewerage system, as now conceived, is out of the question until a copious water supply has been provided. In most of the larger cities provisions for surface drainage preceded the introduction of sanitary sewers. Convenience gradually led to the use of these surface or storm sewers for the disposal of liquid, and then of solid house wastes, the connections for the latter purpose often being surreptitious at first. As public water supplies were introduced and the per capita water consumption greatly increased, the disposal of the water thus brought into the houses often became

even more serious a matter than the removal of surface and ground drainage. This led to the construction of sewers on the combined plan. The expense involved in building sewers large enough to carry off the rainfall was almost or quite prohibitive for all but the larger, closely built cities, so as the need for house sewerage systems increased sewers were built more and more frequently for this purpose alone. About 1850 the separate system was introduced in several English towns. In 1875-76 a separate system of sewerage was built at Lenox, Mass., and in 1880 a more extensive one was constructed at Memphis, Tenn. Both these were designed by the late Col. Geo. E. Waring, Jr. The Memphis system attracted great attention, owing largely to the yellow fever epidemic which preceded and led up to its adoption. Nevertheless, the separate system, often but not always slightly modified to avoid controversy, has been widely adopted in the United States.

Designing a sewerage system necessitates first of all an accurate and complete topographical map of the city or town. The next step is to divide the city into its natural drainage areas, particularly if storm-water sewers are to be built. This done, the location of the main sewer for each district is determined and the tributary population estimated. The grades, or rate of fall per 1000 feet, should be so adjusted as to give self-cleansing velocities. At the same time, economy in construction will keep the sewers as near the surface as is consistent with proper grades and serving the lowest plumbing fixtures in the houses.

The relative advantages of the combined and separate systems of sewerage will depend largely upon the size of the city and whether either pumping or purification is necessary. If either of the latter, and particularly if both, are required, it is highly desirable that the separate system be installed, both on account of the extra cost involved in handling the surface water and of the great disadvantages and difficulties incident to sudden and marked changes in the volume of sewage to be treated at purification works. Another advantage of separate sewers is that they render it unnecessary to place the storm sewers deep enough to serve the bottom of the cellars, thus often saving very heavy deep trenching. The smaller cities and towns find it highly advantageous to adopt the separate system of sewerage, and to construct the sanitary sewers, only, at the outset.

The volume of sewage for which provision must be made is dependent on water consumption and rainfall. In the separate system of sanitary sewers rainfall need not be considered, since it is excluded, but some allowance must be made for the leakage of ground water into the sewers. In fixing the capacity of the combined system of sewers the house sewage scarcely needs be considered except on the laterals serving single short streets, since the maximum surface or storm water to be carried is so far in excess of the house wastes. Ordinarily it is safe to assume that the maximum water consumption is double the average flow, and that 75 per cent. of the latter reaches the sewers, the remainder being used for lawn-sprinkling and for houses not connected with the sewers. On this basis, a city with an average daily water consumption of 100 gallons per capita would have a maximum con