64 



COMPARISONS OF RESPIRATORY EXCHANGE. 



FIG. 26. 



5 10 



FIG. 27. 



15 20 25 



FIG. 26. Tissot spirometer with capacity of 50 liters. 



A, three-way valve connecting air in bell of spirometer with outside air; B, tube leading to 

 inside of bell; C, counterpoise tube compensating for changes in weight of bell; D, siphon tube con- 

 necting C with water in tank; E, flat steel band supporting spirometer; F, wheel over which runs 

 E; H, rubber tube connecting siphon tube with supply tube J; I, branch of supply-water tube lead- 

 ing to tank at L; M, N, overflow tube from tank; O, pointer; P, cock for emptying tank; Q, Q, 

 leveling screws; R, lead counterpoise; Z, opening for gas sampling. 



FIG. 27. Tissot spirometer with capacity of 200 liters. 



All letters appearing in figure 26 are on this drawing and refer to the same parts. G, additional 

 aluminum wheel; S, multiplying pulley; T, movable arc for writing respiration volume; U, electro- 

 magnet. 



