"When this is the case the most effectual method... is, to bring the grate forward till the forepart of it is immediately under the inner edge of the mantle; then build up the vacancy at the back of it, the whole width of the fire-place from side to side, raising it perpendicularly till it is as high as the back of the grate, and then bending it forward towards the mantle, as... fig 4. When it is as high as the workman can reach, let it be suddenly turned backward again, sloping a little upward... then fit a sheet of milled iron to the inside of the mantle, making it slant a little upward toward the back... a small distance above the new... masonry, and extending within a few inches of the back wall... By this construction all the air that enters into the chimney is made to pass immediately above the fire, between it and the heated iron... as the back of the fire-place is bent a little forward above the grate... the heat is likewise reflected into the room with the greater force... [I]f the smoke is accidentally beat down the chimney by a sudden gust of wind, it will be catched by the sheet of Iron, and prevented from coming into the room."