438 



TYLER AND PKKISKNDORFER 



[chap. 8 



Fig. 19 gives the volume scattering function for three samples of com- 

 mercially available "distilled" water together with the computed values of the 

 total scattering coefficients (Tyler, 1960). Fig. 20 gives the average of 30 

 determinations of the relative volume scattering function obtained between 

 Madeira and Gibraltar (Jerlov, unpublished). 



Many of the design features adopted by Pritchard and Elliott (1960) in their 

 Recording Polar Nephelometer for atmospheric measurements could be directly 

 applied to the problem of measuring volume scattering functions in the ocean. 



0.1 



0.01 



0.001 



0.0001 



1 — I 1 1 1 I \ I I r 



h Angular width of beam 



5 = 0.01045 

 5 = 0.00887 



= 0.01587 



160 



200 



Fig. 19. Volume scattering function and total scattering coefficients for three samples of 

 "distilled" water, for peak wavelength 522 mjj., half-band width 56 mjj.. 



Anyone who is seriously considering the development of instrumentation for 

 this purpose would do well to consult their paper. 



In addition to these instruments, two interesting proposals have been 

 advanced for the direct measurement of the total scattering coefficient. The 

 first by Beuttell and Brewer (1949), who, like Waldram, were working on 

 atmospheric scattering, proposed a small Lambert emitter as a source which 

 was to be viewed parallel to its surface at distance h above the surface. Their 

 analysis demonstrates that when the absorption coefficient of the medium can be 



