SECT. 1] CHEMICAL INSTRUMENTATION 121 



The use of a standard oxygen water not only eliminates some of the difficulties 

 connected with the use of previously mentioned standards, it is also the first 

 step in obtaining a complete and unambiguous blank for the complete Winkler 

 method. 



The ratios of oxygen to nitrogen, nitrogen to argon and oxygen to argon 

 can be measured with great precision using the mass spectrometer (see, for 

 example, Benson, 1959; Benson and Parker, 1959, and Richards and Benson, 

 1959). Measurement of the ratios that involve argon offers the means of establish- 

 ing the concentrations of oxygen and nitrogen in sea-water samples if the 

 solubility of argon is accurately known and if the degree of saturation with 

 respect to all three gases is the same during contact of sea-water with the 

 atmosphere. In order to utilize the full potential of this technique, saturation 

 values of all three gases need to be better known. 



The dissolved oxygen electrode system described by Carritt and Kanwisher 

 (1959) and Kanwisher (1959) offers the means of continuous measurement of 

 dissolved oxygen in marine and fresh waters both clean and polluted and, at 

 least in principle, it can be adapted to in situ measurements at all depths in the 

 sea. 



The development of infrared spectrophotometric instruments (see, for 

 example, Smith, 1953, and Kanwisher, 1960) for the measurement of the 

 partial pressure of CO 2 in a gas mixture offers the means of examining varia- 

 tions of CO 2 content in the atmosphere and gas transfer processes between 

 atmosphere and the oceans. The fourteen papers presented in a symposium on 

 the circulation of CO 2 in the atmosphere and the oceans at the General As- 

 sembly of the I.U.G.G. at Helsinki, Finland, in 1960, provide a summary of 

 recent applications and results. Of interest from the point of view of what 

 appears to be necessary in future instrumentation and measurement in chemical 

 oceanography are the results presented by Hood and Ibert. A comparative 

 study of CO 2 partial pressures measured with the infrared instrument and 

 values computed from measurements of alkalinity, pH, temperature and 

 chlorinity by the procedure of Buch et al. (1932) shows large differences. In the 

 open oceans the computed values were always higher than measured and in 

 shallow waters overlying calcareous deposits the reverse was found. 



It is clear that a close examination of the details of both methods is in order. 

 We need especially to examine the value of the constants used in computing the 

 CO 2 partial pressure, as well as the relative rates of the reactions that are 

 involved. A method of measuring pH in sea-water with higher accuracy and 

 precision than can be done at present is needed. Complexing reactions that 

 involve carbonate, bicarbonate and CO2 should be studied and non-volatile 

 alkalinity components — possibly short-lived organic constituents — should be 

 sought. 



References 



Arons, A. B. and C. F. Kientzler, 1954. Vapor pressure of sea-salt solutions. Trans, Amer. 

 Geophys. Un„ 35, 722. 



