           |
                  |  dz/dr     dz/dlon     dz/dlat   |
                   -                                -

               evaluated at the input values of r, lon and lat.
               Here x, y, and z are given by the familiar formulae

                  x = r * cos(lon) * cos(lat)
                  y = r * sin(lon) * cos(lat)
                  z = r *            sin(lat).

</pre><h4><a name="Examples">Examples</a></h4><pre>

   None.

</pre><h4><a name="Particulars">Particulars</a></h4><p