The financially ailing Dance Theatre of Harlem yesterday announced its second $1 million gift in less than a week, a grant from the American Express Co. that will help the renowned company resume a regular schedule.

The American Express grant, which comes on the heels of last week's announcement by the Lila Wallace-Reader's Digest Fund of a $1 million gift, was heralded yesterday by DTH Artistic Director Arthur Mitchell as the beginning of "a new era of hope and promise" for the company.

Earlier this year, facing an estimated $1.7 million deficit, DTH canceled its spring season in New York and laid off its dancers, technicians and some staff from April through September of this year.

Yesterday's grant announcement was made at a press conference in New York jointly by Mitchell and Edwin Cooperman, president and CEO of American Express Travel Related Services Co., who, Mitchell said, was instrumental in securing the boon. Mitchell praised Cooperman for his "vision and commitment to the arts."

The American Express grant, payable in four yearly installments of $250,000, may be used for "various artistic, educational and social programs," according to a DTH statement. In addition, the company will be providing DTH with more than a quarter of a million dollars in "in-kind marketing expertise," including assistance in broadening DTH's Arts Exposure series, which brings dance to children in the form of lecture-demonstrations, seminars and master classes.

The Lila Wallace-Reader's Digest Fund grant consists of an immediate $600,000 toward debt reduction, and $400,000 earmarked for dancers' salaries and operating funds, contingent upon the raising by Sept. 30 of an additional $350,000 to further reduce liabilities.

Mitchell said the first installment of the American Express grant would be counted as part of the required match for the Lila Wallace-Reader's Digest Fund grant, which, he said, would permit the dancers to rehearse without pressure for three months before touring resumes Jan. 1.

"These grants," Mitchell said, "are an indication of confidence in DTH's ability to manage its fiscal affairs responsibly. They will doubtless help us in our further quest for support. Before this, no one wanted to take the first step. Now things are already accelerating in a positive direction."

Mitchell said also that a DTH gala in New York last Wednesday had netted about another quarter-million dollars, and that three smaller grants recently acquired by DTH would enable the company to hold classes from July through September, to help the dancers regain ground lost in the layoff.

Mitchell said that among other strategies under consideration to bolster the troupe's economic future is the possibility of a "second home." "We'd love to have a secure second base in a city like Washington, for instance," he said.