
          796

Let A B C D be built of stone or brick 3 feet
square every way.  a[A] is the door of the furnace b[B], the ash
pit, c[C] is a shallow Iron kettle 20 inches in diameter
& 7 or 8 inches deep placed of the Furnace. B.C. is a
smooth flat stone covering the whole top of the building
in the middle of which is a round hole cut to admit
the kettle. E is a cask, the bottom perforated with holes &
placed over the kettle which is half filled with water, The 
cask is filled with potatoes and being closely stayed all
round the bottom no steam escapes. Cover fitted tight &
a plug short & thick to prevent accident or a piece of lead
with a leather hinge.

[sketch of side and top view of furnace]

[begin vertical text beside sketch]
Steam Boiler from the communcations
of the Board of Agriculture
London.
[end vertical text beside sketch]
        