Etienne-Jules Marey’s device is a small diaphragm (tambour) responsive to pressure. The apparatus amplified the motion of the tambour. Respiration was then recorded on a kymograph.
From Experimental Pharmacology. A hand book. Methods for studying the physiological actions of drugs. By Ludimarr Hermann and Robert Meade Smith. Copyright 1883.
Exhaled carbon dioxide was converted to carbonic acid and weighed. The spirometer is a dry gas meter measuring inspired air. Developed by Dr. Edward Smith. From: British Medical Journal, March 26, 1859, Page 253.
From: Endocrinology and Metabolism. Llewellys Barker, MD, editor. Published 1922. Chapter: The normal process of energy metabolism, John R. Murlin. Page 539.
From: Endocrinology and Metabolism. Llewellys Barker, MD, editor. Published 1922. Chapter: The normal process of energy metabolism, John R. Murlin. Page 532.