CAPILLARY RESPIROMETRY 319 



{Vr — Ad)/VB times their original values, the volume of oxygen or 

 nitrogen released from solution in the reaction chamber during the 

 experiment equals: 



AO2 (dissolved) = aOo^-F/«.Po, y ^yj^^"^ - 1) (c) 



AN2 (dissolved) = aN2,-y/«-PN, y^^f^ - 1) (^) 



These last quantities (c and d) are negative, but they tend to give 

 rise to error in the same direction as the preceding ones (a and b) . 

 All four A values are added, and the sum is subtracted from AFp„. 

 Correction for dissolved carbon dioxide is made by adding the 

 volume that has dissolved to the value for AVp^. 



In the case of respiration experiments the total pressure of the 

 system decreases. Hence: 



AFpo = TiAd 



V. 



c 



.V, + Ad^ 



Since only oxygen is removed during the respiration, the partial 

 pressures of oxygen and nitrogen do not remain equal in the two 

 chambers. In the compensation chamber, the partial pressures of 

 both gases are reduced to ( TV [T^c + -A-dl ) times their original value. 

 On the other hand, the partial pressure of nitrogen in the reaction 

 chamber has been increased to {Vr/IVr — Ad"]) times its initial 

 value, while the partial pressure of oxygen has decreased to: 



( yn \ 



\Vr - Ad + nAdJ °' 



Substitution of these factors for the partial pressure changes in the 

 preceding formulae for the volumes of oxygen and nitrogen dissolved 

 will permit the corrections to be applied. 



(6) Cunningham-Kirk Open-Tube Respirometer 



The capillary tube respirometer of Kalmus (1928) consists of an 

 enlargement at one end of a capillary tube to serve as a reaction 

 vessel while the other end of the capillary is open to the air. The 

 position of the meniscus of liquid in the capillary is used to indicate 



