E.B. White, 86, an essayist, storyteller and conservator of English who delighted, instructed and confounded readers both young and old with such books as "Charlotte's Web," which is about a pig and a spider, and "The Elements of Style," which is about the language itself, died yesterday at his farm in North Brooklin, Maine. He had Alzheimer's disease.

Beginning in 1927, when he joined the staff of the New Yorker Magazine, and continuing through the publication of hundreds of articles and poems and more than a score of books, Mr. White established himself not only as a thoughtful reporter and commentator on his life and times, but also as a master of English prose. A man of enduring curiosity, his topics included world government, arms control and disarmament, impressions of New York City, his farm in Maine and, of course, the animals on it and the sea beyond.

From 1927 to 1938 he was the main writer of the New Yorker's "Talk of the Town" section and he wrote most of its editorials. More than any other he is credited with having set the magazine's tone: thoroughness and clarity, detachment and high concern.

For many years he composed the tag lines on the "news break" items the magazine uses for fillers. They are newspaper items that contain odd typographical errors or make nonsensical or otherwise unintelligible statements. He is said to have thought up the caption on a famous New Yorker cartoon in the days when spinach was regarded as an essential in children's diets. A mother insists that the dish before her small son is broccoli and the boy replies, "I say it's spinach and I say to hell with it."

From 1938 to 1943, Mr. White wrote the "One Man's Meat" column in Harper's magazine. He then returned to the New Yorker. He also contributed to the Atlantic Monthly and numerous other publications.

In addition to "Charlotte's Web" (1952), a modern children's classic in which a spider saves a pig's life by making it a tourist attraction, and "The Elements of Style" (1959), a revision of a small masterpiece on English usage by William Strunk Jr., a professor of Mr. White's at Cornell University, Mr. White's books include "Is Sex Necessary?" (1929), a satire written with James Thurber, his friend and colleague at the New Yorker; "Quo Vadimus? or, The Case for the Bicycle" (1939), a collection of stories and sketches about the complexities of living in cities and suburbia; "Here Is New York" (1949), a famous essay that first appeared in Harper's; "Stuart Little" (1945), a fantasy about a mouse born into a human family which, like "Charlotte's Web," is a delight to as many adults as children; "The Second Tree From the Corner" (1954), a collection of essays about country life; "The Trumpet of the Swan" (1970), another children's book; "Letters of E.B. White" (1976), and "Poems and Sketches," an anothology that appeared in 1981.

J. Russell Wiggins, the editor of the Ellsworth (Maine) American and a former editor of The Washington Post and ambassador to the United Nations, said yesterday that Mr. White told him recently that "he had so much to tell and so little time to tell it."

For the body of his work Mr. White received a Pulitzer Prize in 1978. His honors included the Gold Medal of the Institute of Arts and Letters in 1960; the Presidential Medal of Freedom in 1963; the Laura Ingalls Wilder Award of the American Library Association in 1970, and the National Medal for Literature of the National Book Committee in 1971.

From 1937 until his death, Mr. White's principal residence was in North Brooklin. He was loath to leave it even at the behest of President Kennedy to receive the Presidential Medal of Freedom, and he also sent his regrets to the National Book Committee in 1971. His isolation from the seat of many of the events about which he wrote may have heightened his perspective even as it kept him from personal participation in these happenings.

This perspective, formed by a durable optimism, is expressed in remarks he prepared for the National Book Committee that set forth his view of a writer's place in the world.

"I have always felt that the first duty of a writer was to ascend -- to make flights, carrying others along if he could manage it. To do this takes courage, even a certain conceit," he wrote. "Jacques Cousteau tells us that the sea is dying; he has been down there and seen its agony. If the sea dies, so will Man die. Many tell us that the cities are dying; and if the cities die, it will be the same as Man's own death. Seemingly, the ultimate triumph of our chemistry is to produce a bird's egg with a shell so thin it collapses under the weight of incubation, and there is no hatch, no young birds to carry on the tradition of flight and song . . . .

"But despair is no good -- for the writer, for anyone. Only hope can carry us aloft, can keep us afloat. Only hope, and a certain faith that the incredible structure that has been fashioned by this most strange and ingenious of all the mammals cannot end in ruin and disaster. This faith is a writer's faith, for writing itself is an act of faith, nothing else."

Elwyn Brooks White was born in Mount Vernon, N.Y., on July 11, 1899. His parents were Samuel Tilly White, a piano manufacturer, and Jessie Hart White. He served in the Army briefly in World War I and graduated from Cornell in 1921. He disliked his given name and at Cornell got the nickname "Andy" after Andrew White, the school's founding president.

Following graduation, he drove across the country in a Model T Ford with a friend, worked as a reporter on the Seattle Times for a year, and shipped out as a mess boy on a steamer trading on the Alaskan and arctic routes. When he returned to New York he spent two years working for an advertising agency.

He also wrote, and the New Yorker, which was founded in 1925, published some of his early poetry.

Not long after he joined its staff, Mr. White fell in love with Katherine Angell, the magazine's first fiction editor and herself a major formative influence on it.

They were married in 1929 and had a son, Joel McCoun White, who lives in North Brooklin. There are two stepchildren, Roger Angell and Mrs. Louis Stableford, and three grandchildren. Mrs. White died in 1977.

In 1937, when they moved to North Brooklin and into a house that is now 200 years old, the Whites began raising sheep, geese, chickens and other livestock. Mr. White was particulary fond of pigs and dogs, and he wrote with feeling about the deaths of various ones that he had owned. Another fond topic was the cellar of his barn, a magical place that was known to Charlotte and her kind and was never entirely quiet, even in the dead of night.

Occasionally, he would reach out, as it were, to grasp some event he found particularly outrageous. In 1976, for example, he persuaded Esquire Magazine, the Xerox Corp. and Harrison Salisbury to drop a plan under which Xerox would "sponsor" a piece by Salisbury for the magazine. If Xerox liked the article, it would buy two full-page ads in Esquire. Mr. White said such arrangements were a threat to freedom of the press.

But whatever this slender, retiring man wrote, there were those who were just as interested in how he used the language as in what he had to say. In short, they were taken by his celebrated style.

In his revision of Strunk's famous "little book," a widely used college text, Mr. White said that "style is the writer, and therefore what a man is, rather than what he knows, will at last determine his style. If one is to write, one must believe -- in the truth and worth of the scrawl, in the ability of the reader to receive and decode the message. . . . "

Secure in this belief, the writer is ready for exposure, Mr. White said, and he might profitably pattern himself on the cow in the Robert Louis Stevenson rhyme that was "blown by all the winds that pass And wet with all the showers." "And so must the young writer be. In our modern idiom, we would say that he must get wet all over," Mr. White said. "Mr. Stevenson, working in a plainer style, said it with felicity, and suddenly one cow, out of so many, received the gift of immortality. Like the steadfast writer, she is at home in the wind and the rain; and, thanks to one moment of felicity, she will live on and on and on."

So will the writing of E.B. White.