Duke University announced on Thursday that it had received a gift of $72-million, the largest in its history, from two alumni, Peter M. and Ruth Virginia Lilly Nicholas, of Boston.

The bulk of the money, about $70-million, will be used to expand the reach of the Nicholas School of the Environment and Earth Sciences, which trains environmental scientists and policy makers. The remaining $2-million will finance renovations to the Perkins Library, the school's main library. Duke officials declined to specify the form and timetable of the gift.

The dean of the Nicholas School, William Schlesinger, said in a written statement that he was "delighted" with the gift and predicted that it would strengthen Duke's leadership on environmental policy.

The Nicholases' gift came at the end of the university's eight-year fund-raising drive, which the couple led and which brought in more than $2-billion, a record for Duke.

Peter Nicholas is a co-founder of the Boston Scientific Corporation, which makes medical devices, and is now the company's chairman. The couple, whose three children also are Duke alumni, have given almost $130-million to the university, including money that established the Nicholas School, which was named in their honor.