Hot-air registers in the floor or wall should be carefully avoided in locating gas fixtures. If a light is over or near a register, it will flicker incessantly, and will be a great annoyance. The proper height of gaslights above the floor depends somewhat on circumstances. In ordinary dwellings having a ceiling 9 ft. high or more, side lights should be placed from 5 to 6 ft. high. Pendants may be hung from 6 to 7 ft. from the floor. If the rooms are large and high, the lights of chandeliers may be placed at a height of 7 to 8 ft., or even more. Of course, all lights above 7 ft. high will require the assistance of a torch or step ladder to light them. Low lights should be avoided, because they are tiresome to the eyes. If they must be used, they should be provided with opaque shades. Chandeliers, as nearly as practicable, should be hung from the center of the ceiling. If several side lights are used in the same room, they should be placed at the same height. Care should be taken in locating side lights, to make sure that wooden doors cannot be swung back against them, and be scorched or set on fire. Lights should not be placed where they may be blown out by strong drafts of air, or by the sudden slamming of a door. A gas burner extinguished with a full head of gas on, is very dangerous. Side lights in hallways and vestibules or in churches and similar buildings should be placed at a height of at least 7 ft. A side light should not be placed over a set of tubs if it can be avoided. A better place is at the head of the ironing table Swing brackets should not be used for lighting halls, stairs, vestibules, or other passageways, because of the danger from fire. The light is very liable to be swung too close to the wall, and to be overlooked until the building is set on fire. Swing brackets are always a source of danger when they are located within reach of woodwork or drapery, and therefore are not to be recommended for general use. It is preferable, in most cases, to use instead two single lights on stiff brackets, or else a bracket having two or more rigid arms with fixed lights. In lighting bedrooms, the fixtures should be located so that the bed, wardrobe, dressing case, mirror, etc., may be placed in desirable positions without interfering with the light. The positions of the closets should be noted, and if practicable, the light should be arranged to shine into them, so that the contents may be easily seen. Dressing mirrors should be provided with two stiff bracket lights, one at each side. They should be placed as high as they can conveniently be reached, in order to properly illuminate the head and shoulders of the person using the mirror. In bathrooms, the lights should be set high, so that a person will not be liable to strike them in taking off or putting on clothing. A light should not be located over a bathtub or a wash bowl, or anywhere near them, because of the liability to accident. A kitchen or laundry should be lighted by pendants whenever practicable. If side lights must be used, they should not be placed over the sink or near enough to it to be liable to be struck or be splashed with water. The best place for a side light is usually over the pastry table. Hallways are best lighted by a pendant; if a side light is used it should be placed where it will not interfere with the coat rack, or mirror, or other hall furniture. A pendant in a hallway or vestibule should be set so high that the globes will not be liable to be knocked off by a person who is putting on an overcoat, etc. Stairways should be provided with a light at the top, whether there is one at the bottom or not. A light on the newel post alone is not sufficient to properly illuminate the steps. People having defective sight are especially liable to accident on stairways, and the light should be arranged so as to avoid all shadows that might prove deceptive. The stairway leading from the kitchen to the basement or cellar should be lighted by a burner that is located some distance from the foot of the stairs. If the light is near the foot of the stairs, it is very apt to be struck when large articles are carried past it. ELECTRIC GAS LIGHTING. The arrangement of the apparatus required for electric gas lighting is shown in the accompanying illustration. A k battery of about 6 Leclanché cells c, c, etc., joined up in series, is connected to one terminal of a spark coil k, the other terminal of which is soldered to a gas pipe p. The wire from the free end of the battery is carried up through the house, and branches are run to the burners, as at b, wherever needed. The insulation of this wire must be very thorough, special precautions being taken when it is carried through or along the fixtures. The burners are provided with a chain a attached to a movable contact spring, which is drawn past the burner, producing a spark of sufficient intensity to ignite the gas if it is previously turned on. Gas brackets usually have but a single pipe; the wire should be run on its lower side. A short helix should be made at every flexible joint to prevent breaking of the wire through frequent turning of the bracket. The wire used is No. 20 or 22, B. & S. gauge, well insulated, and colored to suit the bracket. For the house circuits, No. 14 or 16 wire should be used. In multiple gas lighting, a fine wire is run from one burner to another of a group, leaving a small air gap at each one, and a very high-tension current is used, generated by a small frictional machine, causing a spark at each burner. The last contact in a series of burners is connected to the gas pipe. The National Board of Fire Underwriters prohibits the use of electric gas-lighters on combination gas and electric light fixtures, if wired for electric lights and connected. PLUMBING. PLUMBING MATERIALS. DEFINITIONS AND TRADE TERMS. A soil stack is a vertical line of pipe extending through the roof and receiving the discharge of one or more water closets. A waste stack is a pipe extending through the roof, and receiving the discharge from any fixtures except water closets. Waste pipes are pipes that carry the discharge from the fixtures to the soil stacks or drains. Vent stacks are vertical lines of pipe extending up through the roof and ventilating a number of fixture traps or waste pipes on two or more floors. Vent pipes are special pipes provided for ventilating the system of drainage or waste piping and for preventing siphonage and back pressure. A back-vent pipe is a pipe connecting a trap with a vent stack or directly with the outer air. A trap is a device through which liquids and particles of solid waste matter may freely pass, but which prevents the passage of air in either direction. A fresh-air inlet is a pipe extending from the house side of the main drain trap to some point outdoors, where it is open to the atmosphere. Rain leaders, or conductors, are pipes that conduct rain water from roofs to house drains, cisterns, or other places of discharge. Cesspools are receptacles built underground to receive the drainage from a house system. Leeching cesspools are those from which the liquid sewage is allowed to soak into the surrounding earth. Tight cesspools are receptacles that retain all sewage matter, both liquid and solid, until the cesspool is full, when it must be pumped out or otherwise removed. The term house drain is applied to that part of the main horizontal drain and its branches inside the walls of the |