Spirometer
Krogh Wedge Spirometer, early 20th century
A spirometer is an instrument for measuring the air capacity of the lungs. This spirometer was used by filling the rectangular basin with water and having the patient blow through the attached tube. The top piece moved up and down with the strength of the breath and was attached to a marker and a rotating drum to measure fluctuations.
Dr. Francis Weld Peabody, working in the Brigham Respiration Lab, published “Clinical Studies of the Respiration. IV. The Vital Capacity of the Lungs and Its Relation to Dyspnea” in the Archives of Internal Medicine in 1917 (XX, 443) which included photographs of a similar spirometer used in his research here.