64 



COMPARISONS OF RESPIRATORY EXCHANGE. 



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Fig. 26. 



Fig. 27. 



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. 



