The lower trap of a double-trap range must be ventilated. All soil-pipe stacks into which ranges discharge, and fixtures connected to them, must be well protected against siphonage, because the volume of water discharged at one time by a range is sufficient to siphon traps that ordinarily would retain their seals.

Fig. 45. Section of Range Closet, with Siphon-Outlet End..

Urinals. Sectional urinals are made of the same materials and finish, and with much the same types of design, as range closets. They are generally installed in the same classes of buildings as range closets; but such urinals will often be found in the same toilet-room with individual closets. Roll-rim enameled troughs, with back and with simple perforated wash-down flush pipes on the back, are available. Solid porcelain stalls, are also in the market.

Single urinals are usually of porcelain, although some have been made of iron. Pedestal flushing rim urinals, resembling an extra tall water-closet bowl, are now regular market fixtures. The common types are plain or lipped, Fig. 48, made in flat-back and corner designs. Direct-flushing valves of the same type as used on closets, adapted to the purpose, and cocks of various types, are the means of flushing gen-'erally provided for a single urinal. When two or more are placed in one toilet-room, an automatic tank with branched flush pipe is employed. These tanks are of greater variety than those used with range closets. The tilting bucket, pivoted within a tank case, which empties itself periodically by means of the flow of water changing the center of gravity to the unsupported side and tipping it just before it overflows, is a familiar type of automatic urinal - flushing tank.

Fig. 47. Sectional Elevation and Plan of Range Closet Seat with Flushing-Rim Bowl Supplied from General Flush-Pipe.

Fig. 48. Standard Types of Vitreous China Urinals Courtesy of Federal-Huber Company, Chicago.

The standard tank with immovable parts, which siphons automatically, is the most prevalent. A section showing the "Wat-' rous" automatic tank valve is given in Fig.49. Another design consists of p. tank with common siphon, fitted) with a ball cock which opens, instead of closing, as the water in the tank lifts the ball. The interval between flushes is governed by a small bibb cock. When water lifts the ball, the ball cock also admits water, the_ tank filling rapidly. The higher the ball is lifted, the faster the tank fills, so that by the time the water-level reaches a point where water begins to flow over the neck of the siphon, it is coming into the tank rapidly enough to more than keep pace with the overflow necessary to start the siphon. True siphonage, however, empties the tank much faster than the supply can fill it; and the tank is soon empty, leaving the small bibb cock to admit water again slowly to where this action can be repeated.

Fig. 49. "Watrous" Automatic Tank Valve Courtesy of Federal-Huber Company, Chicago.

Fig. 50. Urinal Stalls of Slate, Flushed by Perforated Pipe, with Guttered Floor..

Courtesy of Federal-Huber Company, Chicago .

Individual urinals which siphon by admitting additional water to that which normally stands in the fixture, and various other types, will be best understood from a study of dealers' catalogues. In good work, marble backs and partitions usually enclose the urinals on three sides. Marble and slate stalls of various construction, with channeled and guttered floor, as shown in Fig. 50, all washed by perforated pipes fixed along the surfaces, are frequently used in lieu of specific urinal fixtures. A thick base of slab material is sometimes used, the gutter and drain-hole being cut in it. Cast-iron gutters, galvanized or enameled, with an outlet-end adapted to a soil-pipe connection, are supplied by the makers.

In describing the fixtures and trimmings that have been noticed, only salient features of form and principles of design have been considered. Sufficient guidance to insure intelligent comparison of merits and skilful discrimination in selection, has been given. Catalogue detail and illustration, and a view of the actual goods described therein, should, with what has now been given, insure the fullest understanding of the fixture branch of Plumbing.