the already existing ammonia is fixed by the sulphurous acid in the hot gases from the Destructor. As the process is simple and the heat is furnished, as it were, gratis, it is not wonderful that the concentration is effected economically.

This apparatus consists of a revolving cylinder, 8 feet long and 4 feet 6 inches in diameter, having its ends partially closed by annular rings, and fitted inside with scroll-like plates of thin metal. The liquid is admitted into this cylinder, and as it revolves these scroll-like surfaces become wetted; the evaporation is effected by passing heated gases through the cylinder. As these come into contact with the wetted surfaces of the metal scrolls, rapid surface evaporation takes place, the temperature of the liquid undergoing concentration remaining low-so low that when discharged from the cylinder at about the consistency of treacle, it is rarely, if ever, at so high a temperature as 130° Fahr. The hot gases used for effecting evaporation in the Concretor result from the combustion of refuse material in the Destructor.

The fluid and semi-fluid contents of the pails having been deprived of nearly the whole of their water by means of the Concretor, may either be desicated into poudrette, or be mixed with a portion of charcoal, in order to make a friable, odourless manure. These manures, being extremely rich and concentrated, are of high intrinsic value, more nearly resembling guano than any other manure in the market.

The ancients considered Fire, Air, Earth, and Water as elements. We will regard them as the vehicles for the removal of the refuse of towns.

The water-closet system exemplifies the use of Water; and as it involves the generation and liberation of sewer gases, it also illustrates the use, or rather the misuse, of Air. The purity of streams is held to be of great importance. Yet the whole of the water (save the little lost by spontaneous evaporation) used to transport the offensive matter is-except in the case of towns situated near the sea coast-compelled, sooner or later, to enter the streams. The filth in suspension may be first removed, or it may not; the nitrogen in solution may not be removed, or it may be removed in part; but it is in practice never removed entirely.

The methods now advocated are the employment of Fire and Earth. Solid mineral refuse is purified and reduced by Fire. It is converted from a valueless material into a valuable one, and it is sold as mortar. By Fire the solid vegetable refuse becomes valuable charcoal; from being a generator of offensive odour it becomes a destroyer of such odour. By Fire the organic liquids become valuable solids, and this Fire is furnished by the very refuse itself. The concentrated manure is so valuable that it will bear the cost of transport to great distances, where at last it finds its fitting home in the Earth.

The apparatus for treating refuse in the manner described is made by Messrs. Manlove, Alliott, & Co., Engineers, Nottingham and Rouen.

This method, although new, has early attracted notice. It may be seen in operation at the works of the Manchester Corporation, and Birmingham is adopting the system in the most complete manner,

with the view of extending it, if successful, to the whole of that most extensive borough. Leeds, too, has decided to adopt as much of the system as is applicable to its present wants. When places of such magnitude and importance as Manchester, Birmingham, and Leeds have, after careful inquiry and examination, adopted the system, it will not be considered presumptuous to assert that it is at least worthy of careful attention.

Where it can possibly be arranged, the inspector should contrive to have several depots or yards to cart nightsoil and ashes to. By this method the cost of carting will be reduced, and the evils arising from a large yard will be avoided.

It must also be borne in mind that to try to lower the rates, or to reduce the cost of removing nightsoil, &c., by simply reducing the workmen's wages is a false economy which will never succeed; if we expect a fair day's work let us honestly pay a fair day's wage.

The following is a copy of regulations for nightsoil department, which I have just got printed for our own use, which may be of service in new districts.

RULES AND REGULATIONS TO BE OBSERVED IN
THE NIGHTSOIL DEPARTMENT.

Foremen and Nightmen.

The foremen and men for night duty will assemble at the depot, Street, at 10.30 p.m. each night.

The foreman will instruct his men what part of his

division they are to commence emptying at, and see that they are provided with candles or lamps, barrows, shovels, brooms, and other articles necessary for their work during the night, and will examine all horses before they commence work, will see if any are lame or unfit for work, and if so send them back; and to arrange the time and place for the cartmen to meet them in their respective divisions, and to instruct them where to cart the manure and rubbish, taking care that no manure or rubbish is deposited on any building land, or that any soil be scattered in the streets. The foreman will receive instructions nightly from the inspector where to cart the soil and rubbish, and must carry out all orders given by him. The foreman will be held responsible for the proper cleansing of his division, for the orderly conduct of the men under him, and for the due care of all property committed to his charge.

The men will commence work at 10.30 p.m., and must present themselves at the Chester Street depot to book off at eight o'clock in the morning.

All damage to property to be made good by the person by whose act or default the damage arises. Any person guilty of drunkenness, negligence, swearing, refusing to obey, or other improper conduct will be discharged.

The ashpit men will, before going home each morning, wash the barrows, shovels, and brooms, and put them away. The carters will thoroughly wash the carts and put them into the sheds before leaving at eight a.m.

The inspector will be present at eight o'clock each

morning at the Chester Street yard, at which time he will hear any complaint which the men may have to make.

All the wages will be paid at eight a.m. on Saturday. Any man wishing to leave his employment must give a week's notice before doing so, except in cases of sickness and special permission.

The men are cautioned against taking away any loose property which may be lying in the back yards, although appearing to be worthless or useless. Any man found taking such articles will be handed over to the police authorities.

BY ORDER.