510 



Experiments 



equipped with casters and supporting screws and surrounded by 

 ledges intended to catch the mercury which often falls and would 

 be lost in considerable quantity during the different operations. 



It is clear that by pouring mercury into reservoir B previously 

 set at its highest point, and bringing cock R to position 2, one can 

 expel the air contained in the barometric tube and its chamber 



Fig. 16 — Mercury pump set up for the extraction of the gases of the blood. 

 A. Barometric chamber. B. Movable bulb, in communication with 

 A by rubber and glass tube. C. Mercury bowl with graduated 

 tube to collect gases. R. Three-way cqck which can completely 

 close the barometric chamber (position 1), or connect A with C 

 (position 2), or A with D (position 3)., 



