Patent for a new and improved evaporator and furnace. This design is "compris[ed of] the side walls provided on their opposing faces at one end with the horizontal grooves, and the inclined rearwardly-extending grooves communicating at their lower ends with the grooves, the front end wall having the doors . . . the rear end wall having the . . . collar for the attachment of a smoke-pipe, the bottom plate having its edges secured in the inclined grooves, and the grate-bars having their ends secured in the grooves, the side and end walls being bolted together and thereby rendered separable" (lines 7-20).