function [ n_data, tc, p, pr ] = prandtl_values ( n_data )

%*****************************************************************************80
%
%% prandtl_values() returns some values of the Prandtl number.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    19 September 2004
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    Lester Haar, John Gallagher and George Kell,
%    NBS/NRC Steam Tables:
%    Thermodynamic and Transport Properties and Computer Programs
%      for Vapor and Liquid States of Water in SI Units,
%    Hemisphere Publishing Corporation, Washington, 1984,
%    TJ270.H3, page 265.
%
%  Input:
%
%    integer N_DATA.  The user sets N_DATA to 0 before the first call.  
%    Thereafter, it should simply be the value returned by the previous call.
%
%  Output:
%
%    integer N_DATA.  On each call, the routine increments N_DATA by 1, and
%    returns the corresponding data; when there is no more data, the
%    output value of N_DATA will be 0 again.
%
%    real TC, the temperature, in degrees Celsius.
%
%    real P, the pressure, in bar.
%
%    real PR, the Prandtl number, dimensionless.
%
  n_max = 35;

  pr_vec = [ ...
     13.50E+00, ...
     13.48E+00, ...
     13.46E+00, ...
     13.39E+00, ...
     13.27E+00, ...
     13.15E+00, ...
     13.04E+00, ...
     12.93E+00, ...
     12.83E+00, ...
     12.73E+00, ...
     12.63E+00, ...
     12.53E+00, ...
     12.43E+00, ...
     12.34E+00, ...
     12.25E+00, ...
     12.08E+00, ...
     11.92E+00, ...
     11.77E+00, ...
     11.62E+00, ...
     11.48E+00, ...
     11.36E+00, ...
     11.23E+00, ...
     11.12E+00, ...
     10.91E+00, ...
     10.72E+00, ...
     10.55E+00, ...
      6.137E+00, ...
      3.555E+00, ...
      2.378E+00, ...
      1.000E+00, ...
      0.974E+00, ...
      0.960E+00, ...
      0.924E+00, ...
      0.899E+00, ...
      0.882E+00 ];

  p_vec = [ ...
        1.0E+00, ...
        5.0E+00, ...
       10.0E+00, ...
       25.0E+00, ...
       50.0E+00, ...
       75.0E+00, ...
      100.0E+00, ...
      125.0E+00, ...
      150.0E+00, ...
      175.0E+00, ...
      200.0E+00, ...
      225.0E+00, ...
      250.0E+00, ...
      275.0E+00, ...
      300.0E+00, ...
      350.0E+00, ...
      400.0E+00, ...
      450.0E+00, ...
      500.0E+00, ...
      550.0E+00, ...
      600.0E+00, ...
      650.0E+00, ...
      700.0E+00, ...
      800.0E+00, ...
      900.0E+00, ...
     1000.0E+00, ...
        1.0E+00, ...
        1.0E+00, ...
        1.0E+00, ...
        1.0E+00, ...
        1.0E+00, ...
        1.0E+00, ...
        1.0E+00, ...
        1.0E+00, ...
        1.0E+00 ];

  tc_vec = [ ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
       0.0E+00, ...
      25.0E+00, ...
      50.0E+00, ...
      75.0E+00, ...
     100.0E+00, ...
     150.0E+00, ...
     200.0E+00, ...
     400.0E+00, ...
     600.0E+00, ...
     800.0E+00 ];

  if ( n_data < 0 )
    n_data = 0;
  end

  n_data = n_data + 1;

  if ( n_max < n_data )
    n_data = 0;
    tc = 0.0;
    p = 0.0;
    pr = 0.0;
  else
    tc = tc_vec(n_data);
    p = p_vec(n_data);
    pr = pr_vec(n_data);
  end

  return
end
