<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY INFORMATION EXTRACTED FROM THE CONSOLIDATED
BALANCE SHEET AND THE CONSOLIDATED STATEMENT OF INCOME FILED AS PART OF THE
QUARTERLY REPORT ON FORM 10-Q AND IS QUALIFIED IN ITS ENTIRETY BY SUCH QUARTERLY
REPORT ON FORM 10-Q.
</LEGEND>
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-END>                               MAR-31-1998
<CASH>                                         $42,244
<SECURITIES>                                        $0
<RECEIVABLES>                                 $149,290
<ALLOWANCES>                                    $2,528
<INVENTORY>                                    $98,580
<CURRENT-ASSETS>                              $306,862
<PP&E>                                      $1,200,596
<DEPRECIATION>                                $704,160
<TOTAL-ASSETS>                                $901,828
<CURRENT-LIABILITIES>                         $129,067
<BONDS>                                             $0
<PREFERRED-MANDATORY>                               $0
<PREFERRED>                                         $0
<COMMON>                                          $531
<OTHER-SE>                                    $513,824
<TOTAL-LIABILITY-AND-EQUITY>                  $901,828
<SALES>                                       $215,149
<TOTAL-REVENUES>                              $215,149
<CGS>                                         $147,328
<TOTAL-COSTS>                                 $180,957
<OTHER-EXPENSES>                                    $0
<LOSS-PROVISION>                                    $0
<INTEREST-EXPENSE>                                $952
<INCOME-PRETAX>                                $33,906
<INCOME-TAX>                                   $11,257
<INCOME-CONTINUING>                            $22,649
<DISCONTINUED>                                      $0
<EXTRAORDINARY>                                     $0
<CHANGES>                                           $0
<NET-INCOME>                                   $22,649
<EPS-PRIMARY>                                    $0.42
<EPS-DILUTED>                                    $0.42