Six score and five years ago, on Nov. 19, 1863, President Abraham Lincoln delivered an address on the battlefield at Gettysburg that the world vividly remembers.

Lincoln was dissatisfied with the speech; he called it a "flat failure" and said it "fell on the audience like a wet blanket." He reproached himself later: "I ought to have prepared it with more care."The speech's reception is still in dispute. Lincoln's personal bodyguard, Ward Hill Lamon, is supposed to have said: "I'm sorry to say it does not impress me as one of his great speeches." A Philadelphia newspaperman reportedly asked the president, "Is that all?"

Various accounts have described the people gathered at the Gettysburg military cemetery as "bewildered" and lacking enthusiasm; some of those present said the crowd applauded only courteously, others said that it was silent. Lincoln's audience very well may have been fatigued by the two-hour oration of the principal speaker, Edward Everett. The president himself spoke for less than three minutes.

But his words made an immediate impact on some listeners. Everett, for example, wrote Lincoln the next day: "I should be glad if I could flatter myself that I came as near to the central idea of the occasion in two hours as you did in two minutes." And the Springfield, Mass., Republican advised its readers: "Turn back and read it over. It will repay study as a model speech. Strong feelings and a large brain were its parents - a little painstaking, its accoucheur (obstetrician)."

The judgment of posterity is substantially the same; the Gettysburg Address, only 272 words long, is generally recognized as one of the supreme rhetorical achievements in the English language.

Conciseness, in fact, is one of the elements that make the address so memorable. Theodore Sorensen was struck by this quality when he analyzed the speech before writing President John F. Kennedy's inaugural address. Lincoln, Sorensen observed, "never used a two- or three-syllable word where a one-syllable word would do, and never used two or or three words where one word would do."

The speech is notable also for bringing to full expression a theme that had preoccupied Lincoln all his adult life - the problems and promise of self-government. This is the thought that animates the speech's peroration, which concludes with the words " . . . that government of the people, by the people, for the people shall not perish from the earth."

In a book-length study of the Gettysburg Address, William E. Barton suggested that some of its effectiveness stems from the absence of the pronoun "I." Above all, though, the speech attains greatness because of its generosity of spirit. In this connection, Barton wrote:

"There is no vindictiveness in the Gettysburg Address; no hurling of defiance at the foe driven back from that place; no appeal to passion against those whose invasion of that peaceful spot had cost these lives. There is no hate, no bitterness, no attempt to rouse passion. And there is no apparent effort to keep these elements out of the speech; they are not in the address because they were not in the heart of Lincoln."