spaces. The bottom of the fire spaces _e_ is formed by a sheet iron plate _f_ that is supported by the walls, and the space below plate _f_ serves as an air space through which air circulates by openings _g_ in the front and side walls, this circulation of air tending to keep the plate _f_ cool. The rear of the fire space _e_ extends upward and communicates by an opening _h_ through the wall with the condensing room. In the front wall _c_ is an opening to each fire space _e_ and a door _i_ to each opening. The oil or other liquid is supplied by pipes _k_ that enter from the outside near the rear of the fire spaces. The outer end of each pipe _k_ is fitted with a cup-shaped receptacle _l_, into which the oil will run from the vertical branch of the main supply pipe _m_, so that the amount of oil running into each pipe _k_ may be observed, and regulated by a cock. The pipe _m_ feeds the oil to one or more furnaces, the supply of material to each furnace being separately regulated. In the fire spaces beneath pipes _k_ are placed shallow cast iron drip pans _o_ to receive the oil, and the oil running in faster than it will burn will drop while on fire into the pans _o_, and be spattered into small particles. These pans are changed frequently, access to them being obtained by doors _i_. A slide _p_ is provided in each door _i_ to allow of ventilation when required. The slides and doors should close air-tight. By constructing the fire space _e_ long and narrow, the plate _f_ is more readily kept cool, and the space in front of the point of combustion renders the smoke less liable to escape by the doors. The products of combustion pass through the opening _h_ to the condensing room, which is lathed and plastered, and if the room is sufficiently large a number of furnaces may be fitted to discharge into the same room. This furnace is especially adapted for burning dead oil; but by using burners of suitable construction other oils may be burned, and a superior quality of lamp-black made from mitigated spirits. A very large proportion of the lamp-black now made is derived from the combustion of creosote or anthracene oils from coal tar, or of the residues of shale-oil distillation. The form of combustion chamber varies in different works, but is typified by the following rough sketch of that in use at the Stampshaw Chemical Works (Fig. 11). [Illustration: Fig. 11.--_Apparatus for making Lamp-black from Creosote or Shale Oil._]