Three sizes of Fleisch Pneumotachographs from 1960. From “New methods of studying gaseous exchange and pulmonary function” by Alfred Fleisch, published by Charles C. Thomas, 1960, page 51.
Test system was likely a Fleisch Metabometer. From: Survey of Current Cardiovascular and Respiratory Examination Methods in Medical Selection and Control of Aircrew by A. Scano, NATO Agardograph No. 196, published December 1974, page 58.
From: The Pleuro-subpleural Zone: Its Clinical & Experimental Investigation and Its Practical Importance in Chest Pathology by Josef Skládal, 1942, page 27. Fleisch’s original design used a mirror and a light beam to record air flow on photographic film.