Abstract: A gas chromatographic chamber in the form of an oven is disclosed, including an outer envelope including insulated walls defining the chromatographic chamber which can be made air tight, an inner housing section within that chamber for housing the chromatographic column, and including an air distributor to maintain the uniform distribution of air within the inner housing section, as well as a heater to heat the air therein, non-thermally insulating partitions within the chamber and spaced from the insulated wall to provide a pneumatically insulated space between the insulated walls and the inner housing section, and a fluid circulator to create the controlled circulation of fluid within the pneumatically insulated space to effect the temperature within the inner housing section.