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Graph handdrawn/handwritten on green lined graph paper. 'Powell Duffryn Steam Coal Co Ltd / Curve showing recorded temp of water from Power House / & Compressor Turbo Coolers.' Handwritten on the bottom right hand side of the document is 'Shalford 3 Aug / 20'. Contained within a moroon hardback file with all other documents under accession number 85.184I/4.
