Hercules Inc. had a net income of $43.3 million in the first quarter of 1989, which is equal to 92 cents per share, after net nonrecurring gains of $6.1 million or 12 cents per share.

David S. Hollingsworth, chairman and chief executive officer, said these figures compare to a net income of $39.8 million in the first quarter of 1988, or 82 cents per share.Sales in the first quarter were $681.6 million, an increase from the $661.6 million in the same quarter a year ago, he said.

"We are obviously pleased at the improvement in our operating performance from the second half of last year and the return to an operating earnings level that comes close to the record 1984 first-quarter operating earnings of 86 cents per share," he said.

Hollingsworth said he expects earnings to show continued improvement for the remainder of the year.