102 POLE STEAM-ENGINE. 



" About 1815 or 1816 I was employed by Captain Trevitliick 

 to erect various pole-engines, one of them at Saltram Stream. 

 It had worked at Tavistock ; it was a horizontal high-pressure 

 pole puffer. Captain Samuel Grose was then erecting for Cap- 

 tain Trevitliick a 24-inch high-pressure pole-engine at Beeral- 

 stone, on the Tamar, to drain a lead mine. I assisted Captain 

 Grose. The stroke was about 8 feet. It worked with cross-head 

 and side rods. There were two wrought-iron boilers about 3 feet 

 6 inches in diameter and 40 feet long. The fire and flues were 

 outside. The steam pressure, 60 Ibs. to the inch. I also erected 

 a similar engine with a 20-inch pole at Wheal Treasure, now 

 called Fowey Consols Mine ; and one at Lsgassack, near Pad- 

 stow. Those two had brass poles. It was found that the poles 

 cut and wore in their passage through the stuffing box, the 

 middle wearing more than the ends, causing steam to escape. 

 A similar pole of Captain Trevithick's erecting was then work- 

 ing at Wheal Regent, near St. Austell. 



" In 1818 I saw working at Wheal Chance Mine, near Scorrier, 

 an old 60-inch cylinder Boulton and Watt engine. A pole of 

 Trevithick's was fixed between .the cylinder and the centre 

 of the main beam. High-pressure steam was first worked under 

 the pole and then expanded in the cylinder." l 



The late Mr. William Burral, for many years 

 manager of the boiler-making department at Messrs. 

 Harvey and Co., at Hayle, said : 



" About the year 1815 or 1816 I helped to erect at Treskerby 

 Mine an engine for Captain Trevitliick. Mr. Sims was the 

 engineer of the mine. The engine had the usual cylinder, and 

 close to it one of Captain Trevithick's poles was fixed. The 

 boilers were Captain Trevithick's high-pressure. The steam 

 was first turned on under the pole. When she had finished her 

 up-stroke the steam passed 'from under the pole on to the top 

 of the piston in the cylinder. There was a vacuum under the 

 piston. The stearn-cylinder was 58 inches in diameter, about 9 

 or 10 feet stroke. The pole was 36 inches in diameter, and a less 



1 liecolleetioiis of Captain IF. A. Artha, lY-n/ance, LH7<>. 



