Count Rumford understood that fireplaces
produce radiant heat, and at
about 1795 he came up with a design to
take advantage of that effect.
Although he was an American, Rumford
developed his fireplace in England.
His fireplaces were shallow, with widely
angled covings and light-colored
masonry materials. He experimented
with the shape of the throat "to find
out and remove those local hindrances
which prevent the smoke from following
its natural tendency to go up
the chimney."
Rumford rounded the breast and
reduced the size of the throat to a narrow,
streamlined slit measuring only
about 1/20 the size of the standard fireplace
opening. It forms a nozzle through
which the smoke and air flow at an
increased speed, and