When the oven is required to be heated, the boiler is filled with water, and the fire being kindled in the furnace, the flame passes into the oven, and the smoke escapes into the chimney. The sides of the oven are nearly straight, and turned as sharp as possible at the shoulder, for this form has been found better calculated to retain the heat than any other. The flues to carry off the smoke is over the entrance door, as shown by the dotted line _a_ of the figure here exhibited, exhibiting the plan of the oven. [Illustration] A piece of cast iron covers the space before the door of the oven, exactly level with its floor; the opening underneath is applied to no particular use, but is generally made a receptacle for coal. _Fig. 1_, is an _elevation_ of the oven. The mouth is closed with a cast iron door, in which is a small sight-hole with a slide valve. To heat the oven, the door is thrown back, and a _blower_ is applied to the mouth, so contrived, as not only to cover the mouth of the oven completely, but to enclose also the throat of the chimney; by this contrivance the draft is quickly so much increased, that the oven becomes speedily heated, and if at anytime it is too hot, it is only necessary to throw open the door of the fire place, and to put up the _blower_ for a few minutes; the current of cool air which is thus made to pass through it, soon lowers the heat to the temperature required. In the _blower_ is also an opening of the same kind as that in the oven door, which may be opened and shut at pleasure; the course of the flue is described by the dotted lines at (_b_). _Fig. 2_, is the _blower_ before mentioned for regulating the heat of the oven. _Fig. 3_, is a transverse section from _A_ to _B_ on the plan, looking towards the opening, the fire-place entering the oven at _c_, the crown of the oven is turned with the bricks on end, and in building the oven instead of centering the arch, the whole space is filled with sand, which is well trod down and shaped to the shape which it is intended the crown of the oven shall be of. When the upper work is finished, the sand is dug out at the mouth of the oven. _Fig. 4_, is a longitudinal section of the oven from _C_ to _D_. In this sketch the situation of the flue is evident, and the sectional line of the _blower_, fig. 2, when in its place, is shown by the dotted line _d_, the open space _a_, under the oven, has been before spoken of. Popular Errors concerning the Quality of Bread.