(FORTUNE Magazine) – IN A TINY TOWN in the Vermont hills, in an unpretentious yellow clapboard farmhouse, a country boy named Harry Patten and his rural land-sales company, Patten Corp., are quietly defying a law of physics: What goes up must come down. In the past year profits and revenues at the 22-year-old company have climbed so fast that one financial analyst, Kurt Feuerman of Drexel Burnham Lambert, has had to raise his earnings estimates for it five times in nine months. Patten's stock price has quadrupled since last January, making it the biggest gainer on the New York Stock Exchange in 1986. Over 20 years ago Harry Patten, now 50, made the discovery on which he has built his company: Rural landowners were often unable to locate buyers for their property, while big-city folks frequently had trouble finding affordable country lots. Patten started buying up large pastoral properties, subdividing them into parcels averaging 15 to 20 acres, and selling them, undeveloped, to urbanites seeking a country place. Since going public in November 1985, Patten Corp.'s growth has been explosive. In the first six months of fiscal 1987, ending September 30, profits soared 175% from the same period a year earlier, to $5.6 million, on sales of $38 million. A moneyless upbringing in North Conway, New Hampshire, inclined Patten to extreme conservatism in business. When he was a child, his family was so poor for a time that one Christmas Harry's mother secretly repainted his trucks to make them look like new toys. Harry was indignant. ''When you are that poor,'' he says, ''you never want to go back.'' He keeps most of the risk out of his business by securing potential properties with only a token down payment until all planning and zoning is completed. Then he disposes of them rapidly, usually within eight weeks. Patten says that he has never lost money on a piece of land. Patten was initiated into the salesman's art peddling vacuum cleaners while studying psychology at the University of New Hampshire. After college he was hired as a sales manager for American Central, a large developer of vacation home sites. By 1964 Patten had saved enough money to pursue his lifelong dream of working for himself. He put down $15,000 on a piece of Vermont land, took a partner, and started his business. Ten years later he was doing well enough to branch off on his own. In 1982 he opened his first regional office in Portland, Maine, since then moving into 15 states as far west as Michigan and as far south as Virginia. Says Patten: ''I don't see any reason why we can't be in at least 40 states within ten years.'' Prosperity has not taken the country out of this backwoods tycoon, who claims his best friend is ''my dog, Duke,'' and who often spends lunch hours riding his quarter horse Murdock. His Swedish-born second wife, Elisabeth, a former Pan Am stewardess whom Patten married three years ago, agrees: ''Harry is not on an ego trip,'' she says. He ranks his grandsons right up there alongside Duke on his list of best friends; seven-day workweeks prevented him from getting to know his three children as they grew up. For all his aw-shucks manner, Patten lives the life some of his customers dream about. He owns vacation homes on Lake George, in upstate New York, and in Boca Raton, Florida. He is assembling a stable of racehorses and at least once a year charters a sailboat in the Caribbean or goes skiing out West. ''Rich or poor,'' Patten allows, ''I'd rather be rich.'' Analysts predict that Patten Corp. sales will reach $70 million in fiscal 1987 and $100 million by 1988. Net margins are an impressive 13% and rising. ''This is the most exciting time of my life,'' Patten says. ''Everything I ever dreamed of is happening. My company is doing everything I always knew it could do.'' Shouldn't such success make him a bit nervous? After all, earnings can't increase forever; what goes up must come down. Cite this eternal verity to Harry Patten, though, and he just sits back, grins shyly, and asks: ''Why?''