This invention ensures a rapid, yet regular and uniform burning of the lime, and avoids a blowing of the draft entirely across the kiln, or through one furnace door and out at another. It likewise exposes a greater surface to be acted upon by the fire, which, by this arrangement, is brought in direct and positive contact with the whole mass throughout at the same moment, and thus the difficulty from the outer portion being subjected to a much greater heat than the central portion, is entirely overcome. It is the invention of P. Griscom and C. S. Dean, Baltimore, Md.