adjust to smaller changes in proportionately less 

 time. The response time from zero-oxygen to 

 8.5'ppm is about the same as the reverse, but 

 about 99 percent of readout is achieved in 

 approximately two minutes. 



Undoubtedly, response time will depend 

 upon type of membrane used, temperature, and 

 rate of water circulation. In actual practice, 

 when the instrument is employed in ponds, read- 

 ings can be made at each depth in about one 

 minute, as the change in oxygen from one depth 

 to the next is usually small. 



TIME (MINUTES 



LITERATURE CITED 



American Physiological Society Symposium on 

 Tissue Oxygen Tension. 



1957. Federation Proceedings, Federa- 

 tion of American Society of Experi- 

 mental Biology, vol. 16, no. 3, pp. 

 665-703. 



Carritt, Dayton E . and John W . Kanwisher 



1959. An electrode system for measur- 

 ing dissolved oxygen. Analytical 

 Chemistry, vol. 31, no. 5, p. 9. 



Clark, L. C, R. Wolf, D. Granger, and 

 A. Taylor. 



1953. Continuous recording of blood 

 oxygen tensions by polarography. 

 Journal of AppUed Physiology, vol . 6, 

 pp. 189-193. 



Kanwisher, John . 



1959 . Polarographic oxygen electrodes . 

 Limnology and Oceanography, vol . 4, 

 no. 2, pp. 210-217. 



Lingane, James L. 



1958. Electroanalytical Chemistry, 

 second edition. Interscience Pub- 

 lishers, Inc., New York. 



Figure 8: — Recording of the response 

 time of the platin-um-silver-silver 

 oxide electrode covered with 2 mil 

 Teflon. 



Saila, Saul B. 

 1955. T 



•O2 , an instrument for the esti- 

 mation of temperature and dissolved 

 oxygen in natural waters . The 

 Progressive Fish-Culturist, vol. 17, 

 no. 4, pp. 162-165. 



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