(1) Haldane apparatus for CO2 analysis (Campbell's modification) with two breathing bags, by Aimer Products Ltd., 1960-1970. (2) Haldane apparatus for CO2 analysis (Campbell's modification) with two breathing bags, by Aimer Products Ltd., 1960-1970. (3) Spirometer by the Genito-urinary Company, c.1960 (see 3 stroke nos). Haldane apparatus for CO2 analysis 1960-1970