Poets House and the New York Academy of Sciences are moving to Lower Manhattan. On September 28, NYAS, whose worldwide membership includes more than 23,000 science professionals, will vacate its Neo-Italian Renaissance mansion at 2 East 63rd St. and relocate to a glass-encased floor of 7 World Trade Center, at the north end of ground zero. Poets House, a library and resource center with about 50,000 books and tapes, will give up its SoHo loft space by the end of 2007 and move to One River Terrace in Battery Park City, where it will have a waterfront view from the first and second floors of an apartment building.

“There is a tremendous will to rebuild” after September 11, 2001, the executive director of Poets House, Lee Briccetti, said, adding that the arts are a “life-affirming presence” in Lower Manhattan. “For us it’s a dream come true,” she said. “We will not only to serve poets and readers better, we know we’re going to have a longevity akin to Stanley Kunitz,” a co-founder of the organization, who lived to be nearly 101 years old.The new building is shaped somewhat like a “V” and will also have a new branch library of the New York Public Library. A NYPL spokesman, Herb Scher, said they were in the design phase at the present time.

The NYAS will have sweeping views of the Woolworth Building, Ellis Island, the Statue of Liberty, New York Harbor, and New Jersey. Interestingly, the NYAS will be returning a few blocks away from Barclay and Broadway, where it started in 1817.The vice president and chief financial officer of NYAS, Thomas Kelly, said the academy will move in time for its annual meeting in September.

The spaces occupied by both institutions will grow dramatically. NYAS will increase its usable space 50%, to roughly 30,000 square feet from 20,000. At its uptown site, the NYAS could hold a meeting of up to 100 people; at the new location about 300 people will be able to assemble in one room.

Their children’s room at Poets House will be six times larger, and will be open daily rather than just on Saturdays, as it is now. The doubling of its overall space will allow Poets House to display materials that are in warehouse now, such as full runs of poetry journals. “People learn by browsing,” Ms. Briccetti said, whereas on computer, “you can’t make discoveries in the same way as one can in the physical presence of materials.”

Some downtown trends, such as a residential boom, may help spur rising attendance at nonprofit institutions. The residential population in the financial district has doubled since September 11, 2001, the Lower Manhattan Cultural Council president, Tom Healy, who is also a board member of Poets House, said. According to statistics from the Alliance for Downtown New York, tourism in Lower Manhattan has also grown since 2004.

Poets House and NYAS cite various other advantages of moving downtown. Most notably, Battery Park City Authority, a state public corporation that seeks a mix of uses for its 92 acres, is granting Poets House a free lease through the year 2069. “Our board really recognized this as the opportunity of a lifetime,”Ms. Briccetti said.The rent Poets House will be paying at its current site in Soho will have quadrupled between 1990 and 2007. Over the course of its new lease downtown, Poets House will save about $60 million, which will now go to programs and services — “a much smarter way of performing our mission,” Ms. Briccetti said. She said her board approved the move unanimously.

Mr. Kelly said NYAS also found the move downtown extremely attractive for a number of reasons. “The average market rate for downtown rentals continues to trail Midtown rental rates substantially.Even including this substantial investment in technology infrastructure, the net total cost to the academy is $225 per square foot, which is modest by current standards.” Every floor of the new space will come with 140 tons of cooling capacity already installed by the landlord (normally a tenant expense). In addition, as an occupant of 7 World Trade Center, NYAS will be entitled to subsidized New York State Power Authority electricity, about 30% off normal rates. Mr. Kelly praised Council Member Alan Gerson and the City Council, which provided grant money to be directed toward audiovisual installation.

The old NYAS building, with its white marble façade and central atrium, was built in 1919 as a residence and once held a household of four family members and nine servants. About 70 employees now work there. The outdoor statue of Charles Darwin is being de-oxidized and cleaned and will be placed near the new indoor entrance at 7 World Trade Center as part of a tribute to the academy’s past.

Asked why NYAS was moving, Mr. Kelly said,”The building didn’t meet our needs any more.”The academy had been disappointed at the termination of lease discussions at 1 Madison Ave. when Met Life sold the building to S.L. Green in spring 2005.The academy’s original plan would have called for an auxiliary space nearby at 41 Madison Ave., spreading the organization across two buildings. “We had already designed our new headquarters, that’s how sure we were moving in there.” By then the Academy had no place to move, since it had already sold the current building for $31,250,000 to the billionaire Leonard Blavatnik, whose office told The New York Sun that plans for the building have not been settled yet.

Then around June 2005, Mr. Kelly read an article about 7 World Trade Center. Though he recalled his broker reminding him that he had said NYAS wasn’t looking downtown, the board approved the lease that November.

Was there any opposition? Mr. Kelly said that for a small minority “there was hesitancy but not resistance.”

Ms. Briccetti likewise said, “95 percent have been thrilled. Five per cent have voiced the concern, ‘How do I get there?'”

Bhisham Bherwani, a poet who goes to Poets House about twice weekly, said he will probably miss the old space, but Poets House in its new location will in general have more to offer the community. “It’s good to see it progress.”The organization offers workshops for teens, community lectures, and library programs.

Poets House will feature a staircase through a wall of books in its doubleheight entry space, visible from the park and the street. From the outside, it will be clear “that we’re about books,” Ms. Briccetti said. Its auditorium will open up into an interior courtyard — “a poetry version of the Tanglewood.”

It is great to see “the leap that institutions can make, growing into a new period of maturity,” an assistant vice president for Memorial, Cultural and Civic Programs at Lower Manhattan Development Corporation, Amy Weisser, said.

To finance the move, Poets House has raised $5.8 million of a $6.5 million dollar capital campaign. Led by president Margo Viscusi, the board raised $1.7 million. The city gave it $1 million through the Department of Cultural Affairs, and the City Council matched it. The September 11 Fund gave $600,000, and assembly member Deborah Glick helped Poets House get a $50,000 capital grant. The New York State Council on the Arts gave the organization $15,000, the Lower Manhattan Development Corporation gave an $800,000 grant, and both the Reed Foundation and Tomorrow Foundation gave grants. In addition, Governor Pataki has promised $1 million in capital support, through the Empire State Development Corporation.

Mr. Kelly cited one advantage 7 World Trade Center will have over the old building. “The elevators will be faster.” On East 63rd Street, the elevator “was built by Otis himself and the lighting installed by Edison.”