1028 COTTAGE, FARM, AND VILLA ARCHITECTURE. tenths of all the dirt and smoke produced from gas lights are from the careless way of lighting the burners without taking off the chimneys (funnels). If the cock be fully turned before the match be applied, the gas catches fire with a sort of explosion, and a cloud of dense black smoke is formed : if this be repeated daily on a number of burners, it is no wonder that a ceiling should become coated with soot in a short time. The method I cause my servants to follow is this : every night, when the lights are put out, the chimneys are taken off, and little metal caps are put over the burners to keep dust from settling on their holes while not in use. When they come to be lighted next morning, the caps are taken off, a match is applied, and the cock turned sufficiently to let the gas just catch fire, but no more; the chimney is then set firmly in its place, and the fla.ne raised to two inches high, at which height, if your burners and chimneys be properly proportioned in number of holes and area of openings for air, you have nearly a maximum quantity of light in proportion to the consumption of gas." Fig. 1836 is one of the best and most easily managed burners and chimneys in use in Edinburgh. In this figure, a represents the screw on which the burner is fixed ; b, the burner, drilled with twenty-four holes ; or it may be drilled with thirty holes ; in which case, if the funnel be diminished one fourth of an inch in diameter, it will burn most beautifully, but the flame must be lighted and extinguished very gradually, in order to prevent cracking ; c is the boll of the glass chimney, which is ground inside to the height of the burner, in order to conceal it. A burner of this sort may be placed over each pier of a chimney-piece, as in fig. 1835. Fig. 1837 is the gilt metal cap which is put over the burner in the daytime, when the glass chimney is removed. In fitting up gas apparatus in private houses, Mr. Robison observes, " great advantages result from having the tubing and joints well executed, and of large capacity. Drawn block-tin tubing is the best and safest. Copper tubing is much dearer, and is very apt to become leaky. York cathedral is fitted up with copper tubing, which has been made of confined diameters to limit the expense ; and, although it has cost much more than it would have done if it had been fitted up with tin tubing of due capacity, it will not give the
