Whole body plethysmograph (for measuring lung capacity and airway resistance), by Norris Brothers Ltd., Haywards Heath, 1955-65

This plethysmograph was used to measure the volume of a patient’s lungs. The patient sits on the seat inside the wooden chamber, known as a whole body plethysmograph, and breathes through an external mouthpiece to establish a breathing pattern. Then, the mouthpiece is closed, the patient breathes against it and the changes of pressure are recorded. Air flow and the volume of gases can also be recorded. From knowing pressure changes and temperature, volume changes could be calculated. This example was made by Norris Brothers Ltd, mechanical engineers based in Haywards Heath, Surrey, England, a company which also made Donald Campbell’s record-breaking 'Bluebird' car.

Whole body plethysmographs are still used today but are expensive pieces of equipment.