TABLE II

                 Experimental Design and Results



                Coded Variables     Actual Variables  
   Test No.       x1       x2       Temp,°C      pH     Yield, %

      1            -        -         50          5       40.5

      2            +        -         70          5       49.9

      3            -        +         50          9       61.8

      4            +        +         70          9       78.2