316 On the Construction of Kitchen 



If the door be constructed of sheet iron, it must either 

 be made double, or it must be covered on the outside 

 with a panel of wood. By a double door I do not here 

 mean two doors, but one door constructed of two sheets or 

 plates of iron placed parallel to and at a certain distance 

 from each other ; and so constructed that the air which 

 is between the two plates may be shut up and confined. 

 The two plates or sheets of iron, of which the double 

 door of an oven is made, must not touch each other, 

 except at their edges (where they must join in order to 

 their being fastened together) ; for, were they to lie one 

 flat upon the other, the heat would pass too rapidly 

 through them, notwithstanding there being two of them; 

 but it is not necessary that they should be farther asunder 

 than an inch or an inch and a half. One of the plates 

 may be quite flat, and the other a little convex. The end 

 of the oven must be made quite flat or level, so as to be 

 perfectly closed by a flat surface placed against it. The 

 door is that flat surface ; and the greatest care must be 

 taken that it apply with accuracy, or touch the end of 

 the oven in every part when it is pressed against it ; for 

 if any opening be left, especially if it be near the top 

 of the oven, the hot air in the oven will not fail to make 

 its escape out of it. 



It never should be attempted to make the door of an 

 oven or of a closed fire-place fit, by causing it to shut 

 into a rabbet. That is a very bad method ; for, besides 

 the difficulty of executing the work with any kind of 

 accuracy, the expansion of the metal with heat is very 

 apt to derange the machinery, when the door is so con- 

 structed. 



From what has been said of the necessity of causing 

 the door of an oven to fit with accuracy, it is evident 



