Now in its third edition, this booklet records, slightly edited, a talk given by John Trounson to the Royal Institution of Cornwall on the 10th December 1966. Mr Trounson was a mining engineer in Cornwall all his life and had been interested in the mines, and especially their engines, from a young age. Both amusing and informative, the 44 pages of this publication will give considerable please time after time - and also tell you how the ‘bob’ (or beam) was mounted, as well as give you much other information on Cornish engines. 4 pages of photos and 2 of drawings. Paperback. Trevithick Society