MACAULAY WAS ONCE ADVISED by his landlady that a Mr. Smith was at the door. No name could suggest less, so it was with "utter amazement" that he beheld, when he went downstairs, a portly, white-haired gentleman in a black coat with "a most unclerical wit, whim and petulance" flashing in his dark eyes: "the Smith of Smiths, Sydney Smith." Sydney's best, and almost only, biographer, Hesketh Pearson, took The Smith of Smiths as title for a book published in 1934. In this new biography, Alan Bell doesn't so much improve on it as add fresh facts turned up while preparing an augmented edition of Smith's marvelous letters. It is an elegant and distinguished companion to Pearson's life of one of the most delightful men who ever lived.

No Smith has superseded Sydney, though he is now better remembered for his wit than as the founder of the Edinburgh Review; the man who nearly single-handed achieved Catholic emancipation and contributed vastly to the passage of the 1832 Reform Bill; and as a literary practitioner of polemics rivaled, in W. H. Auden's opinion, only by Hooker, Swift and Shaw. "He is the gayest man and the greatest wit of England," Lord Jeffrey wrote, " and yet to those who know him , this is his least recommendation.His kind heart, sound sense, and universal indulgence, making him loved and esteemed by many to whom his wit was unintelligible."

For all he did to deserve it, one reward eluded him and King George III foretold it early on: Mr. Smith was a very clever fellow, but he would never be a bishop. Even Sydney's best friends feared that one who made people fall on the floor laughing at his jokes, and drove servants from the room strangling and weeping with mirth, could not do justice to a mitre -- though, too late, Melbourne admitted it was "sheer cowardice" not to make a bishop of the man who had done more for the Whigs than all the rest of the clergy together. Sydney himself yearned for what at the same time he laughed at, but he was without the solemnity, snobbery and Tory instincts that would have guaranteed his rise to preferment in the Church of England.

He was born in 1771 to a choleric father who turbulently disliked him. His school days were a long lesson in tyranny, slavery and Latin verse; at Oxford, the inquiry and discussion he relished were abhorred. When he elected to study for the bar, his father forced him into the church. Perhaps a discordant early life is no guarantee of adult misery, though his may have helped make a wit of Sydney -- just as some unloved children grow up to be actors, on center stage at last.

His first country curacy called forth comment of a sort he was to utter from various rustic parishes for some 40 years: "Nothing can equal the profound, the numeasurable, the awful dullness of this place in which I lie dead and buried in hopes of a joyful resurrection." He was first resurrected as tutor to a local squire's son, and in 1798 set off with his pupil not to Germany, where Napoleon's shadow had fallen, but to his second choice, Edinburgh.

Here he made lifetime friends of Scotch philosophers and founded the Edinburgh Review, the progenitor of all serious journals of literary and political criticism. The lively essays and reviews he contributed over the next three decades displayed a lucid, energetic, and versatile style with a genius for startling simile -- as when he compared someone's speeches, in their vigor and length, to the penis of a jackass.

His marriage in 1800 brought him a lifetime of lively domestic contentment with an intelligent and amusing woman made to order for him, and in 1802 he went to London in search of a fashionable pulpit. He was an eloquent preacher, but his sermons contained more levity and opinion than scripture; he had to content himself with Founding Hospital sermons and lecturing on moral philosophy to mobs of ladies who hovered between awe and laughter.

As a diner-out his triumph was unqualified. He became a regular at Holland House, the famous Whig salon where the electrifying Lady Holland and her charming husband entertained a brilliant all-male society. "Think of his possessing Holland House," Sydney exclaimed of his host, " and that he reposes every evening on that beautiful structure of flesh and blood Lady H." But though susceptible to charm he was never overawed by the aristocracy. When Lady Holland commanded him to ring the bell for a servant he retorted, "Oh, Yes! and shall I sweep the room?"

It was the Hollands who secured him his first living, far from their dinner table, in remote Yorkshire -- "twelve miles from a lemon." Sydney resolved to be cheerful: "I have read much in books of simple pleasures and I am about to try whether there be any such pleasures or not." He found some, building a spacious rectory designed by himself and Mrs. Sydney, with bay windows letting in floods of light, walls hung with flowered papars and Piranesi prints, books in colorful jackets and fires in every room, brightened by ventilating tubes of his own invention. All was designed to keep at bay the tendency to melancholy that lay behind the ebullient good humor, making him leery of music and an enthusiast for gas lighting ("Better to eat dry bread by the splendor of gas than to dine on wild beef with wax candles"). His famous letter listing strategems for fighting off depression includes gay rooms and blazing fires as well as shower baths, exercise, amusing books, and short views ("not farther than dinner or tea".) He amused himself with what he called trifles, but they were practical, like the "Universal Scratching Post" which gave pleasure to his animals, among them donkeys disguised as deer by antlers buckled on their heads. He loved teaching his children and servants: "A manservant was too expensive, so I caught up a little garden-girl, made like a milestone, christened her Bunch, put a napkin in her hand, and made her my butler. The girls taught her to read, Mrs. Sydney to wait, and I undertook her morals; Bunch became the best butler in the country." He supervised farming activities with the aid of a telescope and speaking horn, and conveyed his family in all he could afford by way of a carriage, an ancient green chariot named "The Immortal."

He ministered to his parishioners' bodies as well as their souls -- for he had studied medicine in Edinburgh -- with a pharmacopeia from which were mixed such embrocations as they Bull Dog, Peter's puke, Rub-a-dub, Up-with-it-then, and Heart's Delight.

He divided some of his acres into small gardens in which his poor parishioners could grow vegetables. As a county magistrate he saved many of them -- often poachers, to whom he was sympathetic -- from jail; for he thought jails "large public schools, maintained at the expense of the county, for the encouragement of profligacy and vice," and preferred the treadmill as punishment -- efficacious, economical, and exemplary.

His interests ranged outside the county. He detested both Wesleyan fanaticism and Papist irrationality, but was convinced of the injustice of laws that kept Roman Catholics from voting or holding public office. In a series of tracts known as The Peter Plymley Letters his homely analogies made strong arguments. "You deny their freedom to the Catholics upon the same principle that Sarah your wife refuses to give the receipt for a ham or a gooseberry dumpling: she values her receipts, not because they secure her a certain flavor, but because they remind her that the neighbors want it: -- a feeling laughable in a priestess, shameful in a priest; venial when it withholds the blessings of a ham, tyrannical and execrable when it narrows the boon of religious freedom." In a climate created by Sydney Smith the Catholic Emancipation Act was passed in 1829.

A year earlier the Whigs rewarded him with a new living in Somersetshire. His hopes of a bishopric were not quite extinguished, but though Lord Grey's first thought when he became prime minister in 1831 was that now he could do something for Sydney Smith, the best he came up with was a canonry at St. Paul's Cathedral, a snug sinecure that Sydney made a new field for reform and good works. Corpulent and aging as he was, he clambered up the narrow passages and sinuous stairways within the dome to survey every inch of the fabric, and was no less conscientious about budgets, accounts, and the humblest improvements.

Living in London after a near lifetime in a "healthy grave" was a refreshing pleasure in his old age, though he had often sailed down from Yorkshire to feast on the intelligence, ability, wealth and beauty to be found in the metropolis, leaving his family in the dumps -- "melancholy and dull because papa was away," his little daughter told her mother. "He is so merry, that he makes us all gay. A family doesn't prosper, I see, without a papa!" He was not one of those who saved his best efforts for society.

In a lecture on wit he gave some clue to his own style: "flash after flash, with a brisk multiplication of surprises, a continued irritability -- where one nerve no sooner ceases to vibrate than another is struck, and the mind is kept in a constant agitation of pleasure." An example is his remark about three bluestockings whose voices resembled "the clamor of seabirds," followed by a second flash: he feared that if they went to the coast they would be impregnated by a male penguin. He was not a storyteller or wisecracker, but hung his ludicrous fanices on the conversation as it proceeded, laughing not at what he had just said, but what he was about to say -- one of the effects that helped make Fred Allen funny too. And he was never unkind. "You have been laughing at me for the last seven years," someone wrote him, "and you never said anything I wished unsaid."

He knew that life was " a sorry business at best," but he was an 18th century man, without a tragic vision. By the time he died in 1845 the urbane, rational, and humane Whig society he had so amply served and represented was already dead, and within a few years Matthew Arnold's darkly prescient "Dover Beach" would be written. But on a darkling plain the pleasure of Sydney's company survives.