A
chimney sweep is a worker who clears
ash and
soot from
chimneys. The chimney uses the
pressure difference caused by a hot column of gas to create a draught and draw air over the hot coals or wood enabling continued
combustion. Chimneys may be straight or contain many changes of direction. During normal operation, a layer of
creosote builds up on the inside of the chimney restricting the flow. The creosote can also catch fire, setting the
chimney and the building alight. The chimney must be swept to remove the soot. This was done by the
master sweep.