396 On the Construction of Kitchen 



the vacant space, c, a, e, this space was enclosed by 

 means of a circular piece of sheet copper, c, e, / d, 

 with a large circular opening in its centre, of the 

 diameter e, f. This copper, being a little larger in 

 diameter than the cylinder, was firmly attached to it 

 all round by being turned over the same wire, which 

 strengthened and made a finish to the bottom of the 

 cylinder; while the inside edge, e, f, of this circular 

 perforated sheet of copper, being raised upwards with 

 the hammer about an inch, as it is represented in the 

 figure, the saucepan is made of such a form that, on 

 being brought into its place, its bottom is forced down 

 upon the upper edge of this copper, by which means 

 the empty space between the saucepan and its cylinder 

 is closed up below by the copper, and the flame pre- 

 vented from entering it. Sheet iron might have been 

 used instead of sheet copper for closing up this space ; 

 but copper was preferred to it on account of its not 

 being so liable as iron to be destroyed by the action of 

 the flame. 



This contrivance was found to answer so well for 

 preventing the cylinder from being destroyed by heat, 

 that, when it was made of tinned sheet iron (commonly, 

 but improperly, called tin), the tin by which the surface 

 of the iron was covered was not melted by it ; and so 

 completely did it prevent the sides of the saucepan from 

 becoming too hot, that a quantity of fluid of any kind, 

 so small as barely to cover the bottom of the vessel, 

 might be boiled in it without the smallest danger of its 

 being burned to its sides. 



Having found that the sides of the saucepan were so 

 effectually defended by this contrivance from intense 

 heat, it occurred to me that a saucepan of common tin 



