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wells, etc., as such plans must be considered quite unsanitary, and should be invariably discontinued. If excreta are ever allowed to accumulate, it should be in properly prepared receptacles, and after admixture with deodorants.

Removal without Admixture.

In some cases the solid and liquid excreta pass into boxes or tanks, which are emptied daily, or from time to time, and the sewage is at once applied to land without further treatment. In Glasgow the excreta from one part of the town, containing 80,000 people, are now removed every day without admixture, except with the garbage from the houses, and are sent long distances at a profit. If the removal can be made daily, the plan is a good one ; the manure should not be applied in the immediate neighborhood of dwellings, and the Barrack Commissioners have ordered that it shall not be put on land nearer barracks than 500 yards.

In some towns in the north of England (Salford, Halifax, Nottingham), the receptacles are lined with some absorbent material (refuse of cloth manufactures), and at Aldershot with stable litter, intended to absorb the urine (Goux system); in other cases the urine is carried off by a pipe into a drain ; the intention being, in both cases, to make the fecal matter drier, and to delay decomposition.

In others, the soil being removed daily, or at short intervals, is taken to a manufactory, and there subjected to manipulations which convert it into a

manure.

Under the term “Poudrette," manufactories of this kind have been long carried on in France, though they are said not to be very profitable.” At present, however, a portion of the nitrogen of the urea is converted into ammonia, and is united with sulphuric acid, and comes into the market as sulphate. In England, also, there have been several manufactories.

There have been great discussions as to the salubrity of the French poudrette manufactories, and the evidence is that they are not injurious to the workmen or to the neighborhood, although often disagreeable. But the poudrette can take on a kind of fermentation which renders it dangerous, and Parent-Duchâtelet has recorded two cases of outbreaks of a fatal fever (typhoid ?) on board ships loaded with poudrette. In the case of the Eureka Company in England no bad effect was produced on the health of the

men.

Admixture with Deodorizing and Anti-putrescent Substances. Usually, however, some deodorizing substance is mixed with the excreta before they are removed from the house, and they are then at once applied to land without further preparation. Mr. Moule's advocacy of the use of dried earth has brought into prominent notice the great deodorizing powers of this substance, and perhaps no suggestion of late years has had more important consequences. The various substances employed to prevent odor and decomposition are as follows :

* At Carlsruhe, Mannheim, Rastadt, and Bruchsal the excreta are removed in boxes holding about 116 cubic feet (Prussian) every evening. From an experience of eighteen years (1851-1868), the excreta of 6,351 men (mean strength) returned 7,628 florins per annum, of about 1s. 11d. English money per head. In Bruchsal it was 1s. 1d., and in Mannheim 2s. 6d. per head. This rich manure has converted the sandy wastes into fertile corn-fields.

Nearly all the solid excreta of Paris are dealt with in the same way, at the great depôt of Clichy-la-Garenne.

1. Coal and Wood Ashes.—This is a common practice in the north of England, and closets are made with hinged flaps or seats, so that the coal ashes

may be thrown on the sewage. Sometimes screens are used, so that the large cinders are held back, and can again be used for firing. In some towns there are receptacles (middens) intended both for excreta and ashes ; sometimes these are cemented, but are usually porous, and there may be a pipe leading into a sewer so as to dry them. The midden system is a bad one ; even with every care, the vast heaps of putrefying material which accumulate in some of our towns must have a very deleterious influence on the health, and the sooner all middens are abolished the better. The deodorizing effect of coal ashes is very slight. The mixture of coal ashes and excreta usually finds a sale, but the profit is much greater if no ashes are mixed with it. Wood ashes are far more powerful as deodorizers, but it is not easy in this country to have a proper supply.

2. Charcoal. - There is no better deodorizer than charcoal.' Animal charcoal is too expensive, and peat charcoal is cheaper; according to Danchell, 3 ounces of peat charcoal are equal to 14 lb of earth ; and this author states that the cost of charcoal for a family of six persons would only be 1s. 6d. per month. A plan has been proposed by Mr. Stanford,' and is in use at Glasgow, which may obviate the difficulty of price. Mr. Stanford proposes to obtain charcoal from sea-weed ; the charcoal is cheap, and remarkably useful as a deodorizer. After it has become thoroughly impregnated with fæces and urine, the mixture is re-carbonized in a retort, and the carbon can be again used; the distilled products (ammoniacal liquor, containing acetate of lime, tar, gas) are sufficient to pay the cost, and it is said even to give a profit.

The closet used with this carbon is, in principle, similar to Moule's earth closet, with various improvements for more thoroughly mixing the charcoal and sewage.

The advantages claimed by Mr. Stanford's process are the complete deodorizing effect; the small amount of charcoal required as compared with dry earth (three-fourths less required); the value of the dry manure, or of the distilled products, if the mixture is reburnt; and, in the last case (burning), the complete destruction of all noxious agencies. In using it the mixed charcoal and sewage may be stored for some months without odor in some convenient receptacle outside, but not under the house; and Mr. Stanford states that all the house urine can be also allowed to flow into this receptacle. The reburning of the mixture can be done in a gas retort, or a special retort is built for the purpose ; the charcoal left in the retort is returned to the house.

3. Earth.—Since the Rev. Mr. Moule pointed out the powerful deodorizing properties of dried earth, many different closets have been proposed.

Mr. Moule's earth closet consists of a wooden box, with a receptacle below, and a hopper above, from which dried earth falls on the sewage when the plug is pulled up. The earth is previously dried, and about it to 11 lb of the dried earth per head daily is the usual allowance. For a single house, the earth can be dried over the kitchen fire ; but if a village is to be supplied, a small shed, fitted with tiles, below which smoke pipes from a small furnace pass, is required. The earth used in the closet is sufficient to deodorize the solid excreta, and the portion of the urine

At Kreilingen, in Holland, a pail system is in use, where charcoal is employed male from burning town refusé. It appears to yield a product of sufficient value to pay for itself.

* Chemical News, June and October, 1869, and February, 1872.

passed with them ; but the rest of the urine and house water has to be carried off in pipes, and disposed of in some other way. The receptacle is emptied from time to time, and the mixture is stored until it can be applied to land.

The advantages of this plan are obvious; its disadvantages are the necessity of collecting, and drying, and storing the earth, which for cottagers who have little space, and possibly no means of getting earth, is a serious matter. The supply of dried earth to large towns is almost a matter of impossibility, so large is the amount required.' Again, the attention necessary to prevent the house water being thrown in, and to remove the soil at sufficiently short periods, sometimes militates against the success. To obviate these disadvantages, some modifications have been introduced into Moule's closet ; one side of the receptacle may be covered with a grating, leading to a pipe, so that all fluids drain away, and the house water can be thrown in. In another plan, as in Taylor's improved closet, the urine is carried away without mixing at all with the solid excreta. Sometimes the urine thus separated is led into another box of earth, and is thus more easily disposed of, if there are no means of taking it entirely away; or it is passed into a tank, and then used as liquid manure. In another modification (Moser's original form), a partition along the front holds some absorbent substance (sawdust, straw), into which the urine passes, and the solids are thus kept dry. This separation of the urine and solids certainly appears to be an improvement. Dr. Carpenter, of Croydon, reports well of these closets.

The best kind of earth is clay, marl, and vegetable humus; when dried, the clay is easily powdered. Chalk and pure sand are of little use.

The earth system is coming into great use in India, and is carried out with great attention to detail. In those European stations where water is not procurable, Mr. Moule's invention has been a boon of great value, and medical officers have stated that nothing has been done in India of late years which has contributed so much to the health and comfort of the men.' The plan of separating the urine from the fæces has been strongly advocated by Dr. Cornish, of Madras, and would no doubt be attended with great advantages in India if there are means of disposal of the urine. The chief difficulty in the European barracks in India is felt during the rainy seasons, when the mixed excreta and earth cannot be kept sufficiently dry.

In the case of natives of India, however, a serious difficulty arises in the use of the earth system, in consequence of the universal use of water for ablution after using the closet. Every native takes with him a small vessel holding 10 to 20 ounces of water, so that a large amount of fluid has to be disposed of. The usual earth closet does not suffice for this. Mr. Charles Turner, C.E., of Southampton, contrived a closet suitable for the native family ;' it is unfortunately too costly, and possibly a simple iron

2

| For workhouses, prisons, barracks in country places, where there is plenty of labor, and no difficulty in obtaining and afterward disposing of the earth, the plan is most perfect. So also for small villages, if some central authority arranges for the supply of earth, and for the removal of the used soil. For a good statement of the advantages of the earth system, see Dr. Hawksley's paper in the Report of the Leamington Congress on the Sewage of Towns.

Bailey Denton, op. cit., p. 102.

3 An account of the Bengal arrangements will be found in the 2d edition of this work, p. 329, but the plans have been much altered.

* This was done at the suggestion of Dr. Niven, of Bombay. Mr. Turner's closet is described and figured in Dr. Parke's Report on Hygiene for 1867, Army Medical Report for 1866, published 1968, vol. iii., p. 307.

box, with a pipe to carry off the urine and ablution water, would be better suited for the poorer classes.

It appears from the observations of Mr. Fawcus, at the jail of Alipore, that more earth must be used for vegetable than for animal feeders ; the experiment gave 5.1 lb avoir. (24 seers) of undried earth for the daily evacuation of a vegetable-feeding Hindoo. The urine discharge (2 tb) required 8.2 lb of earth. The earth was efficacious in proportion to the vegetable organic matter or humus. In the experiments in this country the clayey matters (silicates of alumina) have seemed to be chiefly useful. In Indian jails and some cantonments the trench system is used ; shallow (1 to 1} foot deep) trenches are dug in a field, and earth is thrown over the excreta ; when the trenches are full, the whole is ploughed up, and vegetables are at once planted, trenches being dug elsewhere ; after two or three crops this portion of the field may be used again. Great importance is attached to the early and repeated cropping of the ground.'

4. Deodorizing Powders.—Instead of charcoal or earth, M.Dougall's or Calvert's carbolic acid powders may be used, and this plan has been largely adopted in some Indian stations. A comparatively small quantity is required, but the smell of the carbolic acid and the cost are somewhat against the plan. Dr. Bond's preparations of Terebene, viz., the Terebene powder, Cupralum, etc., are very efficacious, and have a pleasant odor. Langton-Jones' Universal Disinfecting Powder is inodorous, but not very powerful.

5. Sawdust mixed with sulphuric or carbolic acid. The mixture of sulphuric acid and sawdust has been found to have little efficacy; the carbolic acid has the disadvantage of the odor which adheres to the clothes. Chloralum powder is also mixed with sawdust, and is moderately efficacious.

6. In Germany, Süvern's deodorizer (a mixture of lime, magnesium chloride, and coal-tar) is much used. The Müller-Schür deodorizer is composed of 100 tb of lime, 20 lb of powdered wood charcoal, 10 lb of peat powder or sawdust, and 1 lb of carbolic acid containing 60 to 70 per cent of real acid. After mixing, the mass is put under cover for a night to avoid any chance of self-combustion, and when it is dry it is packed in barrels. Lueder and Leidloff's powder, consisting of ferric sulphate, ferrous sulphate, calcium sulphate, and a little free sulphuric acid, is also much used. It is moderately successful.

Arrangement of Closets on the Dry Plan. As the excreta after being mixed with the deodorizer are in most cases kept for some days or even weeks close to the house, the same rules as to position and construction of closets should be employed as in the case of water-closets. The closet should never be in the basement, but in the roof, or, better still

, in a detached building or semi-detached, and with thorough ventilation between it and the house ; there should be a pipe leading at once to the outer air from the closet, and one from the receptacle.

Two objections have been made to the dry earth system :-1. It is almost impossible to get rid of a certain amount of smell, even with deodorants. 2. The product is not very valuable, according to Dr. Gilbert's analysis, not so valuable as good garden mould, even after the earth has been twice used. The chief value is therefore a sanitary one.

VOL. II.-4

The receptacle itself is usually movable ; but if not, it should be most carefully cemented, so that no leakage may occur.

With these precautions no odor will be perceived; but it is still very desirable that the removal of the soil should be as frequent as possible. In country houses there is no difficulty, but in towns the removal can seldom be more frequent than once a week, and often is only once a month.

The forms of the closet itself are numerous. Those applicable to the earth plan have been already noticed. Colonel Synge, R.E., has patented a closet for Mr. Stanford's charcoal process (the Alver appliance for dry deodorants). In Germany and the north of Europe, where the dry removal, but without admixture with deodorant powders, is in much use, there are various closets in which the urine and fæces are separated.' The “air-closet” of Mehlhouse is said to be a good arrangement for houses. The urine runs into a porcelain funnel fixed on the front wall of the pan, and then into an iron vessel, from which it can readily be removed through a valve ; the solids fall into an iron receptacle at the back part of the pan. A discharge tube passes from the back and top part of this receptacle into a chimney. Two openings in the front wall, which can be closed by valves, can be used as inlets for the air. If a hopper with charcoal or dried earth were attached to this closet, it would be almost identical with Taylor's improved closet.”

Carbonization. In 1869, Mr. Hickey,' of Darjeeling (Bengal Presidency), proposed to carbonize the sewage in retorts, either with or without previous admixture with charcoal. Almost at the same time Mr. Stanford 'proposed the plan already referred to, of the addition of sea-weed charcoal, and subsequent distillation.

In India the difficulty of obtaining a remunerative price for the ammoniacal products, and the large cost of the apparatus necessary for work. ing the plan, have been unfavorable to its success. Carbonization is now being tried in this country, and may possibly be commercially successful. Experience only can show if it is so ; but if it will return a profit, there can be no question that it is an excellent plan in a purely sanitary point of view. The chief money difficulty in the process is the large amount of water which has to be driven off, which greatly increases the expense.

In Manchester Fryer's patent method is in operation, and it is also being applied, in whole or in part, at Birmingham and at Leeds. It consists of a Destructor, which reduces to slag all the more bulky town refuse, such as cinders and ashes, broken earthenware and glass, which cannot be dealt with except by being accumulated in a rubbish heap. This slag is ground, mixed with lime, and sold as mortar. The apparatus is so arranged that none of the heat is lost, while the heated products of combustion pass over

· Roth and Lex (op. cit., p. 454 ) give a good description of these. See also for some good remarks, Pettenkoferis paper on the “Sewerage of Bâle” (Zeitsch, für Biologie, Band iii., p. 273).

? Dr. Bond has also invented a good form of self-acting closet, which separates the urine and fæces. At Manchester and Salford the cinder-sifting closet of Mr. Morrell is in use.

3 The Carbonization or Dry Distillation System of Conservancy, by W. R. S. Hickey, C.E. ; with a note on Dry Sewage, by F. J Mouat, M.D. Darjeeling, 1869.

* A Chemist's View of the Sewage Question, Chemical News, June to October,

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