BOOK REVIEW / Life's all gas and gaiters: Sydney Smith - Peter Virgin: HarperCollins, pounds 22.50

'I AM a very ignorant, frivolous, half-inch person,' Sydney Smith once confessed. Peter Virgin's impeccable biography proves he was anything but. It can be read as a commentated catalogue of the witticisms for which Sydney Smith was and remains famous, and as the fairly arduous progress of a 19th-century English curate.

In an age before talk-show hosts and stand-up comedians, Sydney Smith was both, except that his slot was at the dinner-table or in the pulpit. He was a master of the bon mot in any number of comic shades. He could be delicate, as when he heard a lady lamenting that a certain sweet pea would never come to perfection, and took her by the hand, led her to the plant and exclaimed: 'Permit me, then, to lead perfection to the pea.' He could be epigramatic: 'Shyness looks like a virtue without being a virtue.' He had a gift for exact and absurd imagery: the Brighton Pavilion is as if 'St Paul's had come down and littered'. He could be risque: he imagined 'a certain Scotch lady' so fond of the scriptures that she had emblazoned on her garter 'Set your affections on things above.' He could be bold: 'Your review as I told Jeffrey is long and vigorous like the Penis of a Jackass.'

The story begins with a peripatetic childhood; the Smith family moved house no less than 19 times. His mother, of French Protestant stock, was a great beauty, harrowed by epileptic fits. His father, Robert Smith, was an obnoxious man, given to tantrums and bearing grudges. Sydney's three brothers inherited the worst attributes of their father; their sister Maria was cast in the role of the dutiful daughter who looked after the father and who, partly because of a spinal deformity, never married and never left home.

In 1782, at the age of 11, Sydney was sent to Winchester College, where the schooling was 'comatose', the food 'appalling' and the canings brutal. From there he graduated to New College, where he led, in contrast, an indolent life. Many years later, he tutored all his own children at home, helping them pursue their own interests, in the belief that 'we move most quickly to that point where we wish to go'. Yet, in the belief that suffering would strengthen the character of his son Douglas, Smith deliberately chose for him the notoriously savage Westminster College, 'the most brutal school in England', where the fragile boy was constantly bullied and almost lost an eye in a fight.

Peter Virgin chronicles Smith's career through a series of patrons and uninspiring posts. Most of the notable personages he met - Lord Holland, Lord Melbourne and others - were variously amused and alarmed by his manner and wit, but somehow not sufficiently impressed to set him up for life. Patronage was indispensable for a curate in Smith's time and, as a consequence of never quite becoming a lordly favourite, money was frequently scarce in the household and the bishopric he so much desired was never granted him. Nevertheless, from the pulpit and in the newspapers he fought against foolishness and the abuse of power, defending such notions as Catholic emancipation and attacking such institutions as the English Society for the Suppression of Vice, which condemned bear-baiting but not fox-hunting, and wished to impose a strict Sabbath on the poor.

Virgin associates Smith the satirist with Oscar Wilde, with Edward Lear (Chesterton called Sydney Smith 'the inventor of Nonsense'), with Jonathan Swift. Swift's 'Modest Proposal' of combating the Irish famine by having the Irish eat their offspring is echoed by Smith's denunciation of the practice of sending little children up chimneys: 'An excellent and well arranged dinner,' he wrote in the Edinburgh Review 'is a most pleasing occurrence, and a great triumph of civilised life . . . In the midst of all this, who knows that the kitchen chimney caught fire half an hour before dinner - and that a poor wretch, of six or seven years old, was sent up in the midst of the flames to put it out? . . . What is a toasted child, compared to the agonies of the mistress of the house with a deranged dinner?'

Throughout his life and his writings, Smith remained, so to speak, on the margins of history, although the high points of his career - the founding of the Edinburgh Review in 1802 or his defence of the Reform Bill in 1831 - are remembered, and his witty comments have been dutifully recorded in dictionaries of quotations. Virgin, however, manages to bring forth the complete man, using such details as his style of social intercourse, 'a sort of mental dram-drinking, rare as it was delightful add intoxicating', or the way he laughed, 'infectious without ever being disagreeable or grating'. Virgin gives us an inventory of the objects on Smith's desk; he peeps over Smith's shoulder and describes his writing methods: 'He rarely corrected anything he had written. As soon as he finished a manuscript he would fling it down - 'There, it is done; now Kate, do look it over, and put 'dots to the i's and strokes to the t's' ' - and go out for a brisk walk.' Through these snippets, each of them carefully documented, the reader can easily see the man come to jovial life.

Virgin calls his subject by his first name, Sydney, with agreeable familiarity. There is something warm and trustworthy in this man which, from across a century and a half, calls for chumminess. 'I wish you would tell Mr Sydney Smith that of all the men I ever heard of and never saw, I have the greatest curiosity to see and the greatest interest to know him,' wrote Dickens to his publisher. After finishing Virgin's book, the reader will echo Dickens's sentiment.

Smith died in 1845, at the age of 74, feeling that he had somehow failed in whatever task the Fates had allotted him, but still willing to laugh. 'If my lot be to crawl,' he explained to a friend, 'I will crawl contentedly; if to fly, I will fly with alacrity; but as long as I can possibly avoid it I will never be unhappy.'