| Description | Marked at the top ““Method of calculating tables for Wheal Maid 63 inch cylinder, double 9 feet or 18 feet stroke.” Some of the details have been filled in.
Docketed “Calculations of savings on a 63 inch cylinder.”
[This seven-page printed booklet was intended to form a standard basis for agreements between Boulton & Watt and Cornish mine adventurers. Various parts were blank so that details of individual engines could be filled in. It included details of the performance of the two Poldice engines, against which new engines would be measured.] |