APPENDIX.
DESCRIPTION OF THE LARGE PUMPS BY MESSRS. HARVEY, OF HAYLE FOUNDRY.
Six engines, with a stroke of 10 feet in the cylinder, of the type known as the Single-Acting Cornish Beam Engine, are erected in one house—three on either side of a pit, which is 29 feet in diameter, and 180 feet deep. Those on one side are connected to three pumps of the plunger type; those on the other, to three drawing-lifts, or bucket-pumps.
These engines, as well as all the other permanent engines at this station, were erected by Messrs. Harvey and Co., Limited, of Hayle, Cornwall; as the six engines are similar in every respect, and represent very fairly the type of engine adopted throughout, a description of one will serve for the whole.
All parts of the engines are duplicates, thus any one piston-rod or valve will serve for either engine.
The pumps, valve-boxes, and valves of either type, are also duplicates.
Only a few spare parts, therefore, are required in case any unforeseen accident should disable one of the engines.
Cylinder.The cylinder is of 70 inches internal diameter, by 12 feet long. It is securely fixed in an outer case, leaving a space of 1½ inches between the two, which, when working, is filled with steam direct from the boiler, thus preventing undue condensation in the working cylinder. The con-