Spedding also introduced the practice of "coursing the air". As in other pits, the working areas were ventilated by fresh air, drawn down one half of a partitioned shaft; the air was then exhausted up the other half of the shaft, the air circulation being driven by a furnace at the base of the return half of the shaft: wooden partitioning and doors were used to prevent short-circuiting between feed and exhaust flows within the mine. Spedding improved this by ensuring that after ventilating areas currently being worked the exhaust stream was routed through previously worked areas to eliminate any possibility of firedamp accumulation in unventilated volumes. This practice also spread from the Lowther pits to become standard practice in other coalfields.