willows, which are cut in lengths of about 16 inches and planted about 1 foot apart in one direction and about 14 feet in the other. The cuttings should be planted with their ends nearly level with the ground in order to insure straight shoots. They come into full bearing in the third year, although a fair crop may be got the first year. The maximum growth is attained in about ten years, after which the plant slowly declines, and in the course of fifteen to twenty years it will require reseeding.

The crop is gathered soon after the fall of the leaves by cutting as close to the main stock as possible. The annual yield per acre is stated at from 6 to 7 tons. The price obtained at Wimbledon is about £12 per acre per annum for the rods. This is for osiers; the golden willow yields less and does not bring so high a price as the osier.

The effluent from the Wimbledon farm flows into the River Wandle. As observed by the author, just above the point of junction with the river it was in every way as bright and sparkling as any stream flowing from agricultural lands.

DONCASTER FARM.

As another interesting example of sewage purification and utilization by broad irrigation, we may briefly refer to the farm at Doncaster, which, however, was not visited by the author, but of which it is deemed well to give an account, because Doncaster, while not receiving a prize in the Royal Agricultural Society's sewage farm competition of 1879, was still strongly commended by the committee in their report as an admirable example of thrifty management and an excellent illustration of how sewage can be applied in general farming.

The population of Doncaster is stated at about 30,000 at the present time, with a dry-weather flow of sewage of 700,000 gallons per day. The main drainage works of the town were carried out in 1870, but soon thereafter an injunction was obtained against the Doncaster corporation restraining them from discharging sewage into the River Don. In consequence of this injunction sewage-disposal works were established in 1873. The area available for sewage disposal is about 278 acres, with a very undulating surface. The soil varies between the limits of light sand and stiff red stratified clay. There is also an area of about 20 acres of pasture land laid out for sewage irrigation. The principle of surface preparation followed was, by reason of the undulations, to change the surface as little as possible. According to Mr. Brundell, the designing engineer, no attempt was made to alter the surface, but the flow of sewage was fitted to the surface by the use of main carriers led along the summits and from them by means of contour distributaries the sewage was finally led over the entire area. Figs. 7 to 13 show how the distribution of sewage on such an area may be treated.

The main carriers are of terra-cotta pipe, laid either below the sur

face or in embankments, as may be required. This form of carrier has already been referred to, and is illustrated by fig. 5. The pipes are sometimes worked under a small head. The sewage is pumped from the borough of Doncaster out onto the sewage farm, a 21-inch cast-iron main with a total rise of 22 feet being used for this purpose. A great variety of crops are produced on this farm. According to the report of the judges in the Royal Agricultural Society's sewage farm competition, they have been successful in raising black currants, gooseberries, wheat, barley, oats, rye, beans, potatoes, turnips and swedes, clover, clover seed, rye grass, meadow grass, and osiers. A considerable amount of live stock is also kept upon the farm. In the early days there was some prejudice against the milk produced, but it is now accepted without hesitation. The effluent is stated to flow into the River Don in a state of much greater purity than the water. of the river itself, which is seriously polluted by the towns above Doncaster.

SEWAGE UTILIZATION IN GERMANY.

The sewage farms of Berlin are the most extensive thus far carried Since they exemplify both in their preparation and management the best scientific sewage farming of the present day, attention will be confined to a consideration of them, although descriptions might well be given of the large farms at Dantzic, Breslau, and other points.

BERLIN SEWAGE FARMS.

The information concerning these farms was obtained by inspection by the writer in November, 1894, and from a paper on the sewage farms of Berlin by Mr. Roechling, to be found in Volume CIX of the Proceedings of the Institution of Civil Engineers. The detailed statistical statements, as published annually by the Berlin authorities, for the years from April, 1891, to March, 1893, are also at hand. Inasmuch as Mr. Roechling's paper covers nearly every phase of sewage farming at Berlin, it has been used in some sort as a syllabus in preparing this short account.

At the date of the last census, in December, 1890, the population of Berlin was 1,578,794, the area on which this population is located amounting to about 244 square miles. The area, not only of the city of Berlin, but of the surrounding country, is generally level. The only stream of any size is the River Spree, flowing through the middle of the city, which, however, is far too small to admit of the discharge of the sewage of a city of the size of Berlin without treatment.

The sewerage system, as designed by Mr. Hobrecht, the city engineer, is what is known as the radial system, wherein the entire area has been divided into twelve separate districts, which, so far as the collection of the sewage is concerned, are independent of one another. Each district has a pumping station, from which the sewage is raised

direct to the sewage farms, although in some cases two drainage districts are united to one main. This peculiarity of the Berlin system has determined largely the location of the farms at several different points about the city.

The River Spree flows from west to east through the city. From the systems north of the river the sewage is sent northward, and from the south of the Spree, south; so that, with the exception of a single 12-inch pipe, no sewer or pumping main has been carried under the river. The southern farms are located at a distance from the central part of the city of as much as 12 miles. This makes the disposal of farm produce somewhat difficult. The north and northeast farms are only about one-half the distance of the southern farms from the center of the city, and, consequently, it is stated that the produce there

FIG. 22.-General view of the North Berlin sewage farms, the village of Malchow in the distance. from is far more readily disposed of than that of the farms to the south. This statement is made by the Berlin authorities as a reason why the northern farms show better financial returns than the southern.

The general character of the area included in the Berlin sewage farms is well shown by fig. 22, from a photograph. The most of it is practically level, although there are frequently small eminences attaining a height of from 10 to 15 feet above the general level. The soil is generally light and sandy, although in the northern farms there are considerable patches of clay. The subsoil is coarse, open material for nearly the whole area. Taken as a whole, the soil is well adapted for sewage irrigation.

The total area of the Berlin sewage farms as they existed in 1894 is stated at about 20,000 acres, although only a little over half of this was under irrigation at that time. This great property is not only all owned by the municipality, but is mostly farmed by it as well. During the last few years, however, there has been considerable demand for land by market gardeners, who rent the land and take sewage only when they desire it, whence it has resulted that the area farmed by the city itself has been somewhat lessened. The leased land is first prepared for irrigation by the city and then rented out as required. The annual rental for this prepared land is about $21 per acre, while ordinary land in the vicinity brings only about $8.50 per acre, the difference of $12.50 per acre being due to the increased value of land with sewage irrigation. There has also been a demand for rental of

FIG. 23.-An effluent channel on the Berlin sewage farm.

sewage by the farmers who prepare their own land and only take the sewage as required for the best results. In 1894 sewage was applied to about 1,000 acres in this way.

In considering the results of sewage irrigation at Berlin it should be remembered that the water supply has by metering been kept at a very low point, so that the daily use of sewage amounts to only about 14 or 15 gallons per capita. Including the storm water, the daily flow of sewage averages about 25 gallons per capita. The sewage is therefore more concentrated than that of any town thus far considered.

The rising mains from the pumping stations terminate at standpipes. erected on the highest points at various parts of the farms. These are open at the top and act as safety valves as well as pressure gauges

for indicating the actual head on the mains at any particular instant, this fact being indicated by a float on the inside of the pipe carrying a flag by day and a lantern by night. On account of the location of the standpipes on the highest points, they form landmarks visible from all parts of the farms. The distributing pipes of cast iron start from the standpipes and radiate in all directions to various parts of the farms, their diameters being reduced gradually at their farther extremities. At various places they are provided with sluice valves and side branches which empty into small tanks dug into the ground. The open earth carriers begin at these tanks. There are sluice gates on the distributing pipes at intermediate points as required.

The laying out of the Berlin farms has been done according to the following scheme: The open effluent ditches, of which an example is shown in fig. 23, follow along the lowest levels of the farm; the bottom width is about 18 inches and the side slope 14 to 1. The farm has been thoroughly underdrained, mostly with 2-inch pipes laid on the parallel system at distances varying from 16 to 33 feet. The average depth of the feeders is from 3 to 4 feet. The feeders lead into master drains varying in size from 3 to 6 inches, which finally lead into the main effluent ditches just referred to.

In designing the beds the topographical conditions of the ground were very carefully taken into account, and generally sloping ground was utilized for grass plats, to be treated by broad irrigation. The nearly level portions have been made into filtration areas, and the level ground into tanks in which surplus sewage can be filtered by intermittent filtration as required. The irrigation and filtration plats are, so far as possible, rectangular in form, with areas of from 5 to 6 acres. The tanks, however, are larger. They include plats of ground from 5 to 22 acres in extent, surrounded by embankments about 3 feet in height and from 13 to 20 feet wide at the top, in order to furnish space for wagon roads. In summer the tanks are used as filters to dispose of storm waters, and in winter they are used as reservoirs at such times as, owing to long-continued frost, the land is frozen to a depth preventing ordinary irrigation. The Berlin authorities consider the tanks as a necessary adjunct of any sewage farm operated like that at Berlin, although the degree of purification effected by them is apparently not so high as that of the grass plats or the filtration beds. The 5 or 6 acre plats are also subdivided into what are called quarters, in order to enable the irrigation to be properly applied.

Reference has already been made to the earth tanks at the outlets of the main distributaries. The main carriers, which are merely ditches cut in the ground, illustrated by fig. 4, start from these. They vary in depth from 18 inches to 3 feet, and, entering each 5 or 6 acre plat at the highest corner, pass down one side to the lowest quarter to be irrigated, and so on to the next plat. Secondary car