Table 1: Index of refraction of water as a
function of wave length and water temperature.
----------------------------------------------
  Wave Length
   (Angstroms)   T=10 C   T=20 C   T=30 C

      7065      1.3307   1.3300   1.3290
      5893      1.3337   1.3330   1.3319
      5016      1.3371   1.3364   1.3353
      4047      1.3435   1.3427   1.3417

Table 2. Changes in index of refraction due to salinity
--------------------------------------------------------
salinity
(gm/kg)     increase in n(w)          example
--------------------------------------------------------
   5            0.00097           northern Baltic Sea
  10            0.00194
  15            0.00290
  20            0.00386           bight of Biafra
  25            0.00482
  30            0.00577
  35            0.00673           Atlantic surface
  40            0.00769           northern Red Sea