DESPITE THE DISTINCTLY pot-boiler elements of Keith Harrison`s epistolary novel Eyemouth (Goose Lane, 333 pages, $16.95 paper), I found myself intrigued and sometimes enchanted by his characters` ability to weather the storms of their era (17904815). Opening in the east coast Scottish fishing village of Eyemouth and the nearby capital, Edinburgh, the story follows the adventures and tragedies of Gavin, Jimmy, and later Wilhelmina, as they communicate their concerns to loved ones left at home. This is the Europe of the French Revolution and Napoleonic Wars; we witness the reverberations of its brotherly rhetoric on the recently subdued Scots and the resultant privations endured under "Boney`s blockade." Although on occasion a little forced and clumsy, Harrison`s application of period detail, custom, and dialect is generally convincing. One is often aware, however, that the characters are fleshy embodiments of romantic ideals, rather than peasants polluted with the dogmas of their day. David Hume may have been a celebrated local figure in Edinburgh, but did villagers really discuss his theories of consciousness in alehouses? A minor carp, perhaps. On the whole, this is a diverting, heartwarming study of peasants pummelled by "fate." And finally, unless you`re already a registered scotophile, have a Scots-English dictionary close at hand.