BURNING DRAIN-TILE WITH NATURAL GAS.
The burning of drain-tile with natural gas is about the same as the process of burning with wood or coal, the main differ ence being in the proper regulation of the draft, and the draft required to obtain the best results can only be learned by trial. A round down-draft kiln, 20 feet in diameter, set 13 high in the centre, is the style of kiln which we shall select for describ ing the process. If connected by a two-inch main with the natural gas well at a distance of from one to two miles, the pipe will supply enough gas to burn two kilns, run the engine, and heat the dry shed and dwelling, with 40 pounds pressure.
If the kiln is not given draft enough, the tile will not be burned sufficiently ; if only a little more draft be given than is usual with wood or coal fuel, the fire boxes are liable to be melted down, and the top tile will be too hard and out of shape, while the bottom tile will be too soft. By increasing the draft, and holding the heat longer than with either coal or wood, good results will be obtained. The tile can be dried in less
time than with wood or coal ; but with natural gas the firing should continue about twelve hours longer. With wood the kilns could be finished in twelve hours after the red heat is uniform through the kiln ; but with natural gas, hold it 24 to 3o hours.
While driving off the water-smoke it is necessary to give the kiln but little attention. Fire the kiln in the evening, turning on what gas the tile will stand, and do not visit it any more until next morning, when turn on more gas, and at noon in crease the fires, so that by night the water-smoke is mostly off ; then the fires should be increased so that by midnight the fire boxes, if the clay will allow, should be as hot as they will admit of being without dropping From this time on, visit the kiln every hour or so to see that none of the fire boxes get too high a heat. When the heat is well through the kiln, begin to slacken the fires, so that the top tile may not get too much heat before the bottom gets enough.