PH meter by Doran Instrument Co. Ltd., Stroud, Gloucester [Patent No. 593920, Serial No 3533], with notes and manual PH meter by Doran Instrument Co. Ltd.
Unicam SP500 spectrophotometer c.1960 with two power supply units, one by Unicam, one by Doran Instrument Co. Ltd., Stroud Unicam SP500 spectrophotometer c.1960 with two power supply units
pH meter, in mahogany case BY Doran Instrument Co. Ltd., Stroud, Glos., England, 1957. British patent no.593920 pH meter