The kilns depicted in this drawing from an 1876 atlas have been loaded with tile and the open ends walled up with bricks. Fires for such kilns were lighted and kept slowly burning for the first five hours, and then progressively increased for the next thirty-three hours. Toward the end of the firing, the mouths of the kiln were stopped with ashes to prevent the flow of air from cooling the oven too quickly. A typical kiln consumed approximately four tons of coal per firing to produce hard fired tiles.