Two important Federalist portraits -- one of them a bust of Alexander Hamilton closely related to the image that appears on the $10 bill -- have been given to the Smithsonian Institution's National Portrait Gallery by former ambassador Henry Cabot Lodge.

The portrait, by John Trumbull, was made in 1806, a few months after Hamilton was killed by Aaron Burr. Commissioned by Sen. George Cabot, one of Hamilton's admirers, it had been in Henry Cabot Lodge's family ever since.

Alexander Hamilton sat more than once for Trumbull. Following the duel, Trumbull was commissioned to do the full-length portrait now hanging in New York's City Hall. As was often done in that prephotographic age, Trumbull then produced a number of smaller replicas. These include the one in Boston at the Museum of Fine Arts, a second at the National Gallery of Art, a third at the New York Historical Society, and the picture just acquired by the Portrait Gallery.

Lodge's second gift -- Gilbert Stuart's portrait of Fisher Ames -- is another family heirloom. Ames was an orator, a congressman, and one of Hamilton's trusted counselors. His widow gave the painting to the same Sen. George Cabot, who had edited Ames' papers. Marvin Sadik, the Portrait Gallery's director, says the Stuart is "the most significant work by that artist to have entered our collection thus far."

The Gallery has tried to buy two more important Stuarts -- the Athenaeum portraits of George and Martha Washington -- but they are still in Boston, and whether they will come here still remains in doubt.

"For us these are extremely important acquisitions," Sadik said. Cabot Lodge, some years ago, gave the Gallery John Singer Sargent's portrait of his grandfather, Henry Cabot Lodge. His two most recent gifts, the Trumbull and the Stuart, will go on view today on the Gallery's first floor. t