SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 95 



of I percent carbon dioxide, depending on the concentration in the 

 system, for i millimeter deflection. Calibration is accomplished by- 

 inserting known amounts of pure carbon dioxide into the system by 



^50 



V30 



V20 



^10 



HOO 



390 



380 



v370 



.o 



-^ 



No 



CO added 



2. 



-O © © ®- 



Ui-^O^ec 1 



/ \q^'®~^ — ® — e>- 



77/7? « fSecond^J 



J L -L_ 



iO 30 HO SO 60- 70 



Fig. 3. — Time response of the system. 





- 0H5 



OS 



010 



050 



means of the capillary tube shown to the left of C. The speed of 

 response of the system as a whole is determined by the speed of " mix- 

 ing " of any carbon dioxide change throughout it. The fan used circu- 

 lates the air once around the system in about 5 seconds. Figure 3 



