stroke, or 176 gallons the two; also a 5-inch and an 8-inch plunger, the two raising 25 gallons per stroke.
At the Marsh Pit, two 15½-inch plunger-pumps, with 7-foot stroke, the two raising 114 gallons per stroke, and a 15-inch bucket, raising 54 gallons per stroke.
At the Hill Pit, two 15½-inch plunger-pumps, the two raising 114 gallons per stroke.
At Benacre Bridge, two 15-inch bucket-pumps, raising 108 gallons the two.
Taking the average number of strokes per minute as ten, these pumps represent 36,000 gallons per minute. The actual delivery will be about 20 per cent. less than the theoretical, so that these pumps would raise about 27,000 gallons per minute.
On the Gloucestershire side, at Sea-wall Shaft, there were two 15½-inch plungers and two 15-inch bucket-pumps, raising in all 224 gallons per stroke.
At Green Lane, for the open cutting, two 15-inch bucket-pumps, raising 108 gallons per stroke.
At Ableton Lane, for the bridge, the same.
The total number of pumps provided during construction was thirty, and these were capable of raising 44 million gallons per day.
Four of these pumps—the 37-inch plunger, the 35-inch bucket, and the two 26-inch plungers (the Bulls)—are now permanent pumps.
Permanent Pumps.The permanent pumps provided for the Great Spring and the drainage of the tunnel and cuttings are:
At the Iron Pit, Sudbrook—two 26-inch plungers, with 10-foot stroke, raising 231 gallons per stroke each, the steam cylinders being 50 inches diameter, stroke same as pump; horse-power per stroke from water raised 13·2 per engine, or 15·9 from indicator; ordinary strokes per minute 7, maximum 12; lift for water 190 feet. Also one 35-inch bucket-pump, with 9-foot stroke, raising 376 gallons per stroke; the steam cylinder 75 inches diameter, stroke 10 feet; beam engine, horse-power per stroke from water raised 21·7, from indicator 25·7; ordinary strokes per minute 10, maximum 12; lift 190 feet.
