1893.1 oZo [Bacbe. 



A pipe (a) is carried dowa from the oven of a modified cooking stove, 

 through the floor, and into the cellar beneath the room in which the stove 

 is situated ; or where, because of the impurity of the air of the cellar, this 

 plan is not availal)le, the pipe (a) may be deflected, as shown by the 

 dotted lines (o), and led to the open air through the walls of the room, or 

 in any oilier convenient manner. In order that the air may be properly 

 difl'used and caused to circulate effectively, flanged plates {b) are fastened 

 at top and bottom of the oven, between each of whicli plates and the oven- 

 casing is enclosed a chamber (d). The bottom plate, it will be observed, 

 is perforated at and near the front of the oven, and the top plate perforated 

 at and near the rear, and in the top of the oven-casing (/) a discharge 

 opening is formed, communicating with the chimney flue, the effective 

 area of this opening being governed by means of the common form of 

 sliding damper (g). 



It will be seen that thus the volume of cool, pure air, entering the lower 

 chamber (d), passes thence to the front, and then escapes into the oven 

 through the perforations of the lower (b) plate, there taking the course of 

 diffusion indicated by the direction of the arrows, until it finally escapes 

 from the oven through the perforations in the upper (b) plate. It is evi- 

 dent that the perforations in the two plates may be so located as to com- 

 ■pe\ the air to take any course desired through the oven. 



It will be observed that, although the flow of air is, for convenience, 

 represented by the diagram as taking place within a somewhat determin- 

 ate line, yet that, in point of fact, the air entering the oven will, on account 

 of its immediate and great increase of volume, expand into ever)'' part of 

 the oven, and its consequent flow towards the upper vent will be from 

 all lateral and inferior directions. 



Figure 2 represents a modification of the device illustrated in Figure 1. 



In this case the bottom plate of a cooking-range oven is cast, techni- 

 cally "dished," with a depression (h) near the front end. Both dish and 

 opening are covered by perforated plates (6'). The dish (h) has a neck 

 (7i'), to whicli is adapted a freshair supply-pipe (a), and in the upper fine 

 of the range is located a hinged damper (g'), turned from the outside by a 

 crank handle, by which the flow of air from the oven into the chimney- 

 flue through the upper perforated plate may be governed. 



If it be sought to approach or to rival the excellence of roasting, through 

 the instrumentality of a ventilated oven, five conditions must be fulfilled. 

 The air supplied to the oven must be pure, plentiful, continuous, well-dis- 

 tributed, and reguhitable. 



The ihovement of all air, whether free on the surface of the earth, con- 

 fined in houses, or occupying lesser space, being dependent upon differ- 

 ences of density indifferent parts, and these difierences of density being 

 in turn dependent upon differences in the relative temperature of thos« 

 parts, purity of air for a ventilated oven may be secured with all the other 

 conditions as concomitants. 



