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by the gases conveyed through waste-pipes. Such are some of the manifest advantages afforded by the 'trough ventilator." Giving to every house perfect immunity from the poisonous effluvia of the sewers, it also affords ready means of cleansing pipes.

This "trough ventilator" is not so well adapted for soil-pipes in the centre of a house, or where it cannot open into the external air. In such cases, happily rare, another method may be adopted in securing the ventilation of these pipes. It is by using a "double" soil-pipe, or a pipe of sufficient size divided vertically into two equal chambers by a diaphragm, one channel conveying the soil, the other the gas to the top of house or other outlet. The diaphragm or centre partition running down to a syphon forms the "dip," or trap; the sewer gas being checked by it, ascends the adjoining channel. The air and soil-pipes being thus connected, and forming one pipe, there cannot be the inconvenience mentioned above of the gas being driven down the soil pipe, while their conjunction facilitates also the construction.

The former invention, however, meets the difficulty by giving a vent for the sewer gas without the circumvention of any unnecessary length of pipe, which only retards its escape by confining it. The germ of this method is simply a ventilated syphon, while the idea entertained by most plumbers is that the gas must be carried over our roofs by pipes, an idea not warranted by the necessities of the case. The methods here described are so simple in principle and operation that it is a wonder no similar attempt has previously been made to relieve pipes of their nauseous effluvia except by the addition of separate ventilating-tubes. The energies and ingenuity of plumbers and sanitary engineers are too often spent in the fruitless attempt

1

of devising air-tight traps, or inventing new modes and appliances for regulating the water supply of closets, and numerous patents more or less complicated, as flushing apparati, are constantly placed before the public to secure that end, without touching the greatest evil. No amount of trapping or flushing can remove the cause, but only tends to increase the power and virulence of the gas.

In conjunction with a system of sewer ventilation the "trough ventilator" cannot fail to improve the sanitary condition of towns. It is an appliance of easy application and of very moderate cost.

Since the foregoing observations were written, I have had several opportunities of examining the corrosive action of sewer gas on lead; in some instances, the traps (especially the old D trap) were found honey-combed, or perforated, at the upper part by the action of the gas. These observations lead to the conclusion that

1st. Lead is not altogether so desirable a material as plumbers would have us believe. Plumbers prefer lead because it is the material they are most acquainted with; and because it admits of easy jointing, and is more pliable than iron, &c. Some of our sanitary manufacturers are, however, wisely giving preference for earthenware and tin-encased lead pipes for traps, and the pipe and drains for the conveyance of soil, &c. Glazed earthenware closet traps are decidedly cleaner than lead, and not liable to corrode. Closet pans and syphons are now made in one piece of ware. (See Jenning's patent.)

2nd. We are led to the conclusion that any trap or pipe which harbours the gas, or encloses any space or corner where it can collect, is defective; hence D traps, when unventilated, are more liable than S or syphon traps, to be corroded or eaten through by the gas.

CLOSET APPLIANCES.-It may not be out of place here to speak of the closet appliances in use. There is

the "pan closet," so called from its having a large pan and container under the basin. It has disadvantages from which its rival, the "valve closet" is free. The container or receiver below the basin is apt to become foul, and quickly corrode, and it is further open to the objection that it collects gas in its upper part. In cases where it is used a small ventilating-pipe may be inserted, communicating with the soil-pipe ventilator or shaft. To remedy this liability to become foul, Messrs. Warner, of Cripplegate, London, have provided china containers in lieu of cast iron, which so soon rusts and becomes coated with offensive matter.

The "valve closet," having no enclosing pan, is more direct and clean in its action, the soil at once entering the trap, and the flushing is more concentrated and perfect. There is, also, no space for the accumulation of foul air as in the "pan." Indiarubber-faced valves are sometimes fitted to these closets, making the apparatus noiseless-a great desideratum. The overflow-pipe usually provided to basins of this class is often an injurious addition better avoided, as, unless ventilation be provided as recommended, it only conveys effluvia into the house. The Hopper closet, consisting of a simple basin and trap, or Jennings' earthenware closet is the best.

The overflow-pipes of cisterns are a fruitful source of mischief. They often are untrapped, and connect with unventilated soil-pipes. A small bell-trap is often used, which is of no value whatever, as it soon gets empty by evaporation. A self-acting trap is essential in these cases, especially where the cistern supplies drinking-water, though a separate cistern is best for the latter purpose.

SANITARY CONDITIONS. We may sum up the necessary conditions of house construction as follows:1. Dry subsoil. Houses should not be placed

against the foot of a slope, especially where a bed of clay crops out. Basements should be cut off from the surrounding ground by a bed of concrete or asphalte, and by dry areas below level of basement floor, so as to ensure an open air space all round. Basement floors should be hollow, and ventilated over damp soils. Damp-proof courses should be provided in walls. Drains should never be under a house, but should be accessible; if under, they should be covered by concrete to make them air-tight. Sinks and wash-houses of cottages should be outside walls. Waste-pipes should empty into trapped gratings, so as to leave air-space between outlet and trap.

2. Pure air.-All drain and soil pipes should be trapped and ventilated. Cesspools should, in all cases, be ventilated separately, and placed on the lower surface of strata to prevent percolation into live wells.

3. Warmth.-Walls and roofs should be of hollow construction, and non-conducting materials, and be provided with air gratings. Floors should be rendered fireproof and sound-proof by concrete filling-in between joists or by pugging. Windows in exposed sides should be double; entrances should be protected by double doors.

4. Ventilation, &c.-Ventilation should be provided in all rooms by a proper provision of inlets and outlets so as to circulate the air without draught; attics, and apartments in roofs, and staircase lanterns should particularly be ventilated. Trap-doors should be provided to roofs.

Cisterns should be covered by felt; also all pipes, internal or external, with means of access. Hall's water waste cistern avoids liability to frost. All drains at junctions and bends should have movable lids.

5. Lofty buildings should be protected by lightningconductors; all stoves and ironwork being connected by wire to a well in the earth, or to the water and gas mains.

PART VI.

DESIGN.

SECTION I.-ARCHITECTURAL TASTE.

BEFORE proceeding to consider the principles upon which Architectural Design is based, it may be as well to make some remarks upon the general tendency of art-thought and the transition of taste which the last century has witnessed. These changes or "fashions" cannot be too thoughtfully considered by the young architect, as indicating both the natural tendency, or reactionary impulse, of the mind for variety; and also as affording a very reliable means of testing the fictitious, and discriminating between truth and error; between mere sentiment and the immutable laws of design in art. Since the publication of the first editions of these "Hints" architecture has undergone considerable changes in regard to its manner or style. Greek art, and the traditions of classic Italy, were at one time the "rage." Architects pinned their faith to the "five Orders," and few ventured to depart from those proportions which the finest examples of Greece and Rome afforded.

Every column, moulding, and intercolumn was nicely proportioned by the "module" or diameter of the column to within a "minute," or sixtieth part; and the student who could accurately draw the "five