that the farms considered had been in operation does not exceed 3 per cent per annum, the result comparing favorably with that obtained somewhat more recently at Berlin.

We are obliged to conclude, therefore, that properly managed sewage farms are not detrimental to health.1

NUMBER OF BACTERIA IN SEWAGE-FARM EFFLUENTS.

By way of showing the degree of bacterial purification effected by sewage farms we may refer to the following observations made by Prof. E. Ray Lankester on the sewage and effluent of the Oxford sewage farm, England, and the water of the Oxford River, into which the effluent from this farm discharges. These observations were made on the given dates in the summer of 1892.2

Comparison of number of bacteria in sewage and in river near Oxford, England.

Professor Lankester states that the most important fact brought out by these studies was that the species of bacteria which belong characteristically to sewage (B. coli communis, etc.) were not found in the sewage, but only fluviatile species. He further states that it may be asserted in a general way that the effluent contains no more bacteria, nor other kinds of bacteria, than are to be found in other streams draining from agricultural lands in the neighborhood.

SEWAGE FARMING IN ENGLAND.

Having taken a rapid review of the general subject of sewage irrigation, it is now in order to briefly describe a few of the more notable examples of sewage farming abroad and in this country. First may be considered the English farms, and then, briefly, those of Germany and France. Five examples are given from England typical of prevailing conditions, these being the Croydon Beddington farm and the Leamington, Birmingham, Wimbledon, and Doncaster farms. There

1See paper by Dr. Alfred Carpenter, of Croydon, read before the British Medical Association in 1888. Dr. Carpenter lived for many years in the immediate vicinity of the Croydon Beddington farm.

Statement by Prof. E. Ray Lankester to the Royal Commission on Metropolitan Water Supply, Appendix C, 61.

are probably more sewage-purification works in England than in any other country, but they all present merely variations in details.

In regard to the present views of English engineers, sanitarians, and sewage-farm managers, it may be stated that the consensus of opinion, as it appeared to the author in 1894, was decidedly in favor of the land purification process. If for any reason it is necessary that the effluent from sewage-purification works should pass into a stream which is the source of a water supply, the further consensus of opinion appeared to be that it should, before receiving the land treatment, be clarified to the extent of removing all of the suspended and a small portion of the dissolved matter by some of the more inexpensive chemical processes. The same views, it is believed, are now held in the United States by many competent engineers, although the effluents from high-grade intermittent filtration areas are also unobjectionable.

CROYDON-BEDDINGTON FARM.

Croydon Borough is a suburb of London, with a stated total population of about 115,000 to 120,000, the daily flow of sewage amounting to an average of 4,500,000 gallons. In addition to the Beddington irrigation farm the borough has another farm at Norwood. The area at Norwood is stated at 105 acres and that at Beddington 525 acres, making a total area of 630 acres, of which about 525 acres are actually under cultivation. Inasmuch as the Beddington farm is the more interesting of the two, we will confine our description entirely to it. At Beddington 425 acres are in irrigation, the balance of 100 acres being occupied by the farm buildings, cottages, roads, and the ground too high to be reached by the sewage, which is delivered upon the farm by gravity. The buildings upon the Beddington farm include 4 farmhouses, superintendent's residence, and 14 cottages. This farm was designed and laid out by the eminent English sanitary engineer, Baldwin Latham. When irrigation first began, in 1860, the original area was much less than at present, additions having been made from time to time to accommodate the growth of the town and consequent increased flow of sewage.

A considerable portion of the soil is an open, porous, black loam from 6 to 10 inches in depth, with occasional areas of a light, free, open soil, but all suitable for irrigation. The subsoil is gravel and sand. The farm has a gentle slope from east to west averaging from 1 in 150 to 1 in 250. The River Wandle flows to the south and west of the farm. The first underdrains were laid under a portion of the farm about fifteen years ago. They have been laid wide apart, and in some cases as much as 9 feet in depth; conductors vary from 4 inches to 2 feet. The chief value of these drains is that they help to dry the land out quickly after the sewage is taken off.

The slope of the soil of this farm is so uniform that about the only

preparation required was a slight adjustment of the surface by raising at some places and lowering at others, but so little of this as not to cut through the top soil. The main carriers along the higher portions of the farm are usually of concrete about 3 feet wide, and level or nearly level where the ground permits. The secondary carriers are also in some cases of concrete. The small distributaries are made with a plow, a furrow being laid from the secondary carriers down the line of greatest descent and at a distance from each other of from 40 to 50 feet, in order to flow the sewage over all portions of the area to be irrigated. Heavy galvanized-iron or wooden stoppers are used at varying distances down these trenches. For this work, when the field is undergoing irrigation, a man passes over and places the stops at each

FIG. 17.-Outdoor ensilage of rye grass at Beddington.

point as needed. On the lower side of each field there is a collecting ditch, into which the effluent water passes. The arrangement of the farm is such that the effluent of the first irrigation is passed over the fields a second time, and, when necessary, a third time. In this way very efficient purification is attained. The time occupied in passing through three irrigations is stated at from three to four hours. As to the loss of water from irrigation, the general statement is made that about 2 out of every 3 gallons of sewage passed onto the farm flow off as purified effluent, the third gallon having been either evaporated or absorbed by the land or growing crop.

The principal crops raised are Italian rye grass, pasture, mangolds, and other root crops, osiers, cereals, and cabbage. Rye grass, the principal crop, is stated to exhaust itself on this farm in about three

years, when it is followed by a crop of mangolds, cabbages, or wheat and oats, with a return after that to rye grass. Five or six cuttings of rye grass are grown in a season. Mangolds yield especially well here. Wheat and oats are grown chiefly for the straw. Enough horses are kept for working the farm. About 200 milch cows are also kept for the purpose of consuming the large quantities of rye grass and roots grown.

As to the purification effected at Croydon, no analyses appear to have been made in recent years. From a series made after the farm had been in operation for about ten years it is concluded that the purification attained then was very efficient.

This farm was visited by the author on October 20, 1894. At that time of year the main crops had been removed, although fine fields of cabbage and mangolds were still standing, and a casual glance at them indicated the successful results in sewage utilization obtained at this farm. The last cutting of rye grass of the season was in progress at that date, and in one field an outdoor rye grass ensilage stack was in process of making, as illustrated by the photograph, fig. 17. Several pasture and cut rye-grass fields were under irrigation, the sewage coming onto the same black and filthy, and absolutely without any preliminary straining or purification. The first irrigation showed marked improvement; the second showed still more improvement, and, finally, after the third, the effluent flowing in the ditches appeared as bright and sparkling as any stream of water flowing from agricultural lands. The floating matters of the sewage are stated to have never given any trouble on this farm.

Mr. Greenwood, the farm superintendent, stated that 100 acres additional had just been purchased, and it was contemplated to purchase about 50 acres more in the spring, making the total area of the farm when this is done about 675 acres. During the year 1893 the farm is stated to have paid £3,000 more than all cost of operation, not including, however, interest on first cost.

As to the cost of laying out this farm, it may be remarked that by reason of the use of concrete carriers and distributaries the first cost was higher than would now be considered necessary. At the present time the laying out of the farm could be accomplished for somewhat less than the actual cost when done thirty-seven or thirty-eight years ago.1

There are a number of country houses along the highways leading through or at the sides of this farm. The author was accompanied on his visit by Lieut. Col. Alfred S. Jones, V. C., a well-known English sanitary engineer, whose residence is on the banks of the River

This is not intended as in any degree a criticism on the work of Mr. Latham. In 1858-1860, when this farm was laid out, we had much less knowledge derived from experience in sewage irrigation than at present. Probably the leading idea was to make permanent work, and from this point of view the work must be considered very successful. Since 1860 we have learned that sewage can be distributed in ordinary earth channels equally well, thus not only materially decreasing the first cost, but rendering it easier to realize a profit on sewage-farm investments as well.

Wandle, near the point where the effluent from the Beddington farm enters that stream. In the course of a walk about the farm, a stop was made at the residence of a gentleman whose garden plat of 3 or 4 acres is surrounded on three sides by the irrigation fields of this farm. As to the question of nuisance, the owner stated that no nuisance had ever been created by the sewage irrigation that he had considered in any degree objectionable, although there were occasionally slight smells in warm weather. When the place was first occupied by him, over twenty years ago, he had rented, but on the expiration of the lease he had bought the freehold of the property, because it suited him, and he had not considered in making such purchase that the value of the property was in any degree injured by the presence of the sewage farm. He also said that a neighboring cow yard, where a considerable number of cows were kept for the purpose, as already stated, of feeding sewage-grown produce, was regularly a source of much more serious effluvium nuisance to the neighborhood than ever came from the farm itself. At the time of the author's visit, in October, absolutely no smell of any sort could be detected in any part of the irrigated fields.

The statement was made that no difficulty with the irrigation had ever been found here in the severest cold weather. Ice forms on the surface, but the sewage flows underneath it, sinking away into the ground, and the purification still going on, although probably a larger area is required in winter for a given purification than in warm weather. As one of the model English sewage farms, the Croydon Beddington farm has been frequently described.1

LEAMINGTON FARM.

In the Royal Agricultural Society's sewage farm competition, to which reference has already been made, one of the prizes awarded was to the sewage farm at Leamington Springs, which is owned by Lord Warwick. This farm was visited by the author on October 25,

1894.

The borough of Leamington Springs has a stated population of 27,000, although there is considerable variation in the population, owing to the large number of visitors during the season. The sewage is delivered by the borough upon a farm of about 400 acres, owned by the Earl of Warwick, at a distance from the borough of about 2 miles. The borough receives £300 per year for the sewage, and its responsibility ceases when the sewage is delivered at the point agreed upon on the farm, which is at an elevation of about 131 feet above the pumping station. In the agreement it is stipulated that the effluent from the farm shall be purified to the satisfaction of the conservancy commission of the River Leam, into which it finally flows.

1See Crimp's Sewage Disposal and Rawlinson and Read's Report on Sewage Disposal as made for the Local Government Board in 1876. An extended series of analyses of the sewage and effluent not only of this farm but of the Croydon Norwood farm may be found in this report.