Environmental chamber by Laboratory Thermal Equipment Ltd., Greenfield, near Oldham, Manchester, England, serial no. 33585 (a thermally insulated, humidity conditioned chamber with trays for samples, glazed inner door and heavy outer door), mounted on a metal frame base, with a 'Xactline' two-channel temperature recorder for Pt/PtRh thermocouples type 7052/1 serial no 2179FB by Pye Ether Ltd., Stevenage, Hertfordshire, England, on top (possibly modified), 1971-1980. Environmental chamber by Laboratory Thermal Equipment Ltd. 1971-1980