system is not perfect. The figures which I gave as to temperatures, are figures I ascertained myself by experiment on the different sewers during the past year. One gentleman asked me about flushing. I would explain what I meant. My remarks in the paper were these. You can flush the sewers as much as you like, but that does not touch the old sewers, simply because the old sewers are upon private property crossing the back gardens of the houses.

Mr. ESCOTT asked about the power of fixing the ventilating pipes. We have power now, under the model bye-laws, and under most new bye-laws, to compel persons to ventilate their house drains, but we have no power to compel them to fix ventilators from the sewers against their houses. As a matter of fact, I have got, by persuasion, as many as fifty-I think it is-of these shafts erected in various parts of the town, against private houses, with the consent of the owners.

THE MANURE-DRYING APPARATUS IN USE AT BIRMINGHAM.

By A. M. FOWLER, M.I.C.E.

FARMER'S system of disposing profitably of town excreta has proved a very great success, but as yet has only been tried by the Birmingham Corporation. The merit of the system lies mainly in the disintegrating or pulverising power of the machine during the whole time it is at work. The pulverisation of the mass under treatment is effected by the interlocking of the scrapers attached to the two interior steam-heated centres, which revolve in twin pans, each having a longitudinal section removed, which pans are bolted together to form one twin cylinder. This twin cylinder is cased for steam heating to heat the wet stuff undergoing evaporation and the vapours are exhausted by a powerful fan, and passed to a condenser, and thence to the sewer, after being disinfected.

Economy is also effected by the Farmer machines through the accuracy with which they are made. The interior surface of the pans is bored out to a true cylindrical form, so that the scrapers cut off everything on this surface, and prevent caking. The necessity of this will be more readily understood when it is stated that excreta is a non-conductor of heat, and if it is not cleaned from the interior surface of the pan it has the effect of insulating the heat of the casing from the bulk of the stuff. The results obtained at Birmingham have exceeded the anticipations of what these pans were constructed to do. There are three machines on other principles at work, viz. 13 feet long and 4 feet 6 inches diameter by one maker, and two 13 feet long by 6 feet 6 inches diameter by another maker, and at the time this report was made one of the "Farmer" machines. The total amount evaporated in one week was 160 tons, out of which the five one-cylinder machines it is said did 49 tons, the remaining 111 tons being treated entirely by the "Farmer" machine. Again, it is also stated that, taking the pulverising power of the machines, the dried manure came from the five pans in lumps, whereas the "Farmer" machine made it into powder, which makes it more valuable for spreading over the land. The Farmer process is a new one, but statistics

of its more recent practical results can be obtained at any time from Mr. Wilkinson, Superintendent of the Birminghan Interception Department, where the machines can be seen at work. The following technical description of the machine may help to give a better insight into its construction and acquaintance with its principle.

It may be said to consist of a fixed steam jacket or casing of a twin cylindrical form, with closed ends in which cylinder jacket or casing are mounted two hollow steam-heated axles, each provided with a series of blades, or beaters, which latter are set, by preference, at varying angles, so arranged and geared together, that when they revolve they pass between each other.

This twin cylinder steam jacket is cast or formed into about eight sections, bolted together by means of external flanges, and capable of resisting a steam pressure of 70 lb. per square inch. Each cylinder has about one-third its circumference removed, the two open sides are placed together, and united by flanges and bolts, so that when the blades or beaters revolve upon their axis, inside the two cylinders, the said blades will interlock and break up and disintegrate the semi-dry material and prevent it forming into lumps (whereby the moisture is trapped) as it sometimes does in machines of one cylinder.

The ends of the blades or beaters are provided with scrapers which are so pitched around the axes, that are of such a width that no two scrapers scrape the same surface, but that all the scrapers in conjunction work in one revolution of each of the said axes, and entirely scrape or clean the inside surface of the steam-heated casing. This casing or twin cylinder steam jacket is made of cast iron in longitudinal parts, or segments to be convenient for transport or erection. The joints are planed to the necessary angles and the segments are bolted together by external flanges, after which they are bored out to make a true cylindrical internal surface, enabling the scrapers to be set close to the said surface to prevent any coating of non-conducting material from caking thereon to retard evaporation.

Thus the heat is greatly economised and the evaporation greatly accelerated. The hollow sections are connected by branch steampipes attached to the main steam-pipe, and the condensed water is removed by similar pipe connections.

The hollow axes are geared together by a pair of equal-sized spur wheels, so that they revolve in opposite directions; one of these spur

wheels being driven by a spur pinion, keyed on a shaft, which is actuated by a steam engine (preferably of the double-cylinder diagonal class) or by other suitable power.

The vapours produced by the drying of the excrement or other matter are drawn off at the top of the machine by a fan or other exhauster, and are sent to a condensing apparatus.

The "wet stuff" to be dried is poured in through openings at the top, and the manure powder is discharged through balanced doors at the bottom.

VISITS.-1. GAS WORKS.

By the kindness of Mr. F. B. Ball, gas manager, the Members were shown the plant recently erected at the gas-works for the treatment of the residual products. That part of it which is devoted to the treatment of the tar consists of two 10-ton stills with the necessary condensers, separating vessels, and receivers. There is also a room set apart for the manufacture of crude carbolic acid. Adjoining this is the anthracene house, where the heavy anthracene oils are filtered, then pressed by hydraulic power, and the pressed anthracene is packed in barrels and sold to the producers of artificial alizarine. After being treated for carbolic acid the naphthas are passed on to the rectifying house, there to be washed with rectified sulphuric acid and again distilled to produce benzol, toluol, solvent naphtha, and burning or heavy naphtha. This is as far as the process is carried at these works, the further treatment of the benzol being left to the aniline colour makers. The plant for the treatment of the ammoniacal liquor was erected by Messrs. John Abbott and Co., of Gateshead, and consists of two 15-ton stills with their accompanying saturators, settling tanks, and evaporating pans, being on what is known as the close saturator principle. The total quantity of sulphate produced in twelve months is about 320 tons. St. John's carburetter and condenser was also shown to the Members and its action explained.

2. ROCHDALE MANURE WORKS.

The Members proceeded to the Manure Works, where they were met by Mr. Alderman Taylor, Chairman of the Health Committee, who conducted them through the works, and explained in detail the different stages of the operations now being carried on towards a

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solution of that much-vexed question, the Disposal of Town Refuse. Descriptions of the Depot and the character of the work carried on have appeared in previous volumes of the Proceedings (vol. iii. p. 204; vol. v. p. 104), but as considerable changes have been made in the mode of dealing with the excreta and the ashes, the following short description has been prepared. The works are situated about 660 yards from the centre of the town. The closets are on what is known as the Rochdale Pail System, with a roofed ash-place at the back, containing tub for the reception of the house refuse. The excreta pails are removed weekly in specially designed vans, each van containing 24 pails; the full ones on being removed from the closets are hermetically sealed by a cover invented by the late manager (Mr. Haresceugh), and are replaced by clean pails, each having had placed therein a small quantity of deodorant. The tubs containing the house refuse are removed weekly or as required; 8346 tons of excreta, and 15,503 tons of house refuse have been collected this last year, the staff required being 2 inspectors, 33 drivers, 21 conductors, 33 horses. The ashes and refuse are tipped into a shed, containing riddling machines, which remove all the fine ash, which is eagerly fetched by farmers to use as an absorbent in their shippons, and for mixing with liquid manure. The tin cans and similar articles are taken out and disposed of from time to time. The cinders, vegetable, and other refuse, are used solely for generating heat and steam throughout the premises, the clinkers resulting therefrom being ground in a mill with lime into mortar, which has a ready sale and is also used by other departments of the Corporation. On entering the works, the vans, after being weighed, proceed into a large shed, which is hermetically sealed, the two doors only being opened when required for the admission and exit of the vans; the pails are removed from the vans, and placed on a large table of a hydraulic lift, which raises them to a higher floor, where they are emptied into two tanks, when they are returned, and washed, and deodorised, before being placed in the vans, which are also similarly treated after every journey. The excreta is run from the tanks into revolving cylinders, 12 feet long, by 6 feet 6 inches to 6 feet taper diameter. These cylinders or machines, have been designed and patented by Mr. Haresceugh, and are the outcome of several years' experience at these works in attempting to convert the excreta into a marketable manure. The cylinder revolves on four friction rollers, there being fixed inside the cylinder a movable arm or scraper for keeping the mass