He is the Lincoln of the legends. He is great-souled and war-wearied. The crack in the glass negative predicts the bullet's path. There is in his dark eyes relief and profound patience. The surrender at Appomattox had come the day before. He had just four days to live.

The last photograph of Lincoln, taken by Alexander Gardner is part prophecy, part icon. Because the negative was broken in the developing process, just one print was made.

It has been acquired by the National Portrait Gallery, where it goes on view today.

It is but one of 5,420 portraits from the era of the Civil War that come to the museum from the spectacular collection of Frederick Hill Meserve, an insatiable collector who died at 96 in 1962. The Gardner is the only paper print in the acquisition. All the other portraits--of Lincoln and his wife, of generals and actors, senators and freaks--are little pictures made from life in Mathew Brady's studios. And all of them are original negatives on glass.

The Portrait Gallery today opens its Frederick Hill Meserve Collection Gallery, a room whose first exhibit--the Gardner and some 70 modern albumen prints made from those glass negatives--does little more than hint at the wealth of the collection.

That hoard of portrait photographs was acquired for $913,000, its appraised value, but not that much changed hands. Most of the price--$700,000--was provided by the Congress in the form of a tax credit to Meserve's estate.

"There are collectors who are hobbyists, fans, faddists, enthusiasts, eccentrics, cranks, bugs," wrote his friend, Carl Sandburg. "Meserve is the Zealot."

Frederick Hill Meserve grew up in wild Colorado, and worked there as a cowboy, as a hunter and surveyor, before moving East to attend MIT. His zealotry began in 1897 when Meserve, then 31, walked into Bang's Auction Room on Fifth Avenue in Manhattan. Caught up in the excitement there, he bid $1.10 for a package of old photographs "wrapped in brown paper and tied tightly with string."

"That night," he recalled many years later, "I had my first experience of the sensation of intoxication--that intoxication, the only kind I have ever experienced, that comes from the possession of a rare find." He had purchased, sight unseen, more than 100 salt prints made by Brady of earlier daguerreotypes. Meserve, who soon decided to find the pictures needed to illustrate a private edition of his father's Civil War diaries, would buy photos all the rest of his life.

In 1902, he purchased, as a group, the glass-plate portrait negatives the gallery now owns. He left them to his daughter, Dorothy Meserve Kunhardt, from whom they were acquired.

Most of them are formal, strangely touching images of more or less illustrious Americans posing patiently and stiffly in their finest clothes. Actor Edwin Booth, whose brother shot the president, strikes a Napoleonic pose. Laura Keene, the actress, who was performing at Ford's Theatre on that fateful night, wears a floor-length gown. Henry Ward Beecher, the golden tongued Brooklyn preacher, leans nonchalantly on Brady's studio table. Samuel F.B. Morse, inventor of the telegraph, shows off his white beard. Lincoln is here, too, both in full face and in profile. Brady's profile portrait was the image used for the Lincoln penny.

"From the very first," said Brady, "I regarded myself as under obligation to my country to preserve the faces of its historic men and mothers."

Brady and his helpers, one of whom was Gardner, photographed generals (Grant, Sherman, Sheridan), writers (Longfellow, Hawthorne), explorers (Charles Wilkes), politicians (Stephen Douglas, Cassius Clay, Jefferson Davis, Hamilton Fish), diplomats and soldiers, journalists and painters--and the midgets and the giants, the fat women and thin men, that P.T. Barnum showed in his museum in New York.

Photography was still relatively new when these glass negatives were made. "Our children's children may look into our very eyes, and judge us as we are," observed The New York Times on Oct. 6. 1860. "Perhaps this will be no great advantage to us, but, in our children's children's name, we ought to thank Mr. BRADY and those who labor with him to this end."

The gallery has announced that the inaugural selection "will remain on view indefinitely" in the second-floor Meserve Gallery; "future exhibitions will be drawn from the remainder of the collection at regular intervals." There are more than enough photographs in its acquisition to fuel small exhibitions for many years to come.