LOOKING for quick passage to another world and another time? Either of these books will serve well. Both are set in the early 19th century, in or around Australia, and both are engaging works of imagination that combine action, suspense, and vivid introspection. Beyond that, however, they're utterly different."The Nutmeg of Consolation" is the 14th in a series of seafaring novels by British author Patrick O'Brian, who blends deft storytelling with an encyclopedic grasp of maritime lore and natural history. O'Brian's central characters are Jack Aubrey, a gentle tyrant of a sea captain who worships the traditions of His Majesty's Navy but has a deep compassion for his men, and Steven Maturin, ship's doctor, naturalist, and intelligence agent. Much of the appeal of this tale comes from the relationship between these longtime shipmates. Their skills, resourcefulness, and good fortune see the crew through shipwreck, piracy, a near disastrous engagement with a French man-of-war, and, finally, a dispiriting layover in Sydney Harbor, then the capital of a cruel British penal colony. There's no shortage of adventure in this novel, but it's more than an adventure story. The long, hit-and-run fight between the Nutmeg of Consolation, as Captain Aubrey christens his new ship, and the more heavily gunned Frenchman is more a test of endurance and seamanship than firepower. The book's pace and interest spring largely from wry dialogue and the many dimensions of its characters. Jack Aubrey habitually tries, and habitually fails, to come out with clever turns of phrase that might rival the wit of his more learned friend. Stephen broods about a fortune lost because of a bank failure back in London and finds refuge from his sometimes overheated thoughts by chewing on coca leaves - until the ship's rats deprive him of that escape. O'Brian's writing is loaded with language of sea and sail, as in this appraisal of the Nutmeg: "She was neither brisk nor lively with the wind much abaft the beam, but on a bowline she was as fast and weatherly as a man could desire... ." Heavy-going for the landlubber, perhaps, but usually done with such adroitness that it only adds notes of authenticity, whether the technical meaning is fathomed or not. When you put this book down, a taste of salt air lingers, as does the acquaintance of two extraordin ary men. Rodney Hall's new novel, "The Second Bridegroom," leaves a strong impression too, both for its psychological and symbolic depth and its layered, nearly tactile description of the Australian wilderness. The story pours through the thoughts, and pen, of a teenage boy from the Isle of Man, whose gift for printmaking takes him, first, to a shop in Oxford, where he tries to sell his forgery of a classic work, then on to the penal colony in the antipodes. The terrorized youth's flight for freedom into the domain of gum forests, kangaroos, and Aborigines entwines his history as the son of a Manx smuggler with the timeless "chaos" of a wild continent where history - in the Western sense - had barely begun. The youth, who hates the colonizing impulse and whose rebellion against oppression leads him to murder (so he thought) a tyrannizing fellow convict, is protectively encircled by a group of Aborigines. They seem to revere him, though they never speak to him and scarcely look at him. Over months of trekking through the untouched wilderness, he learns to eat what they eat and walk silently, as they walk. BUT there's nothing quiet about the youth's thinking, which is torn by memories of his family, guilt, and youthful longings. Like fresh-fallen leaves in the multilayered forest, he myopically journeys through, those concerns are just a surface. Beneath them lie the symbols - is he the "second bridegroom" foretold in Manx legend, whose coming would restore the freer life before kings, churches, and prisons? Can he woo his goddess-wife - who in his imaginings has become personified, ironically, in the English wife of the colonizing master whose bonds he escaped - to the life of freedom he has discovered in the wild? No chance. That's the verdict of history, and it comes with a thud in the closing pages of this narrative, most of which is framed as letters from the youth to the supposed object of his love. This is far from an easy read. The allusions often pass as faintly seen as an Aborigine gliding through the forest. The themes of tension between nature and civilization, freedom and society, however, are there like massive tree trunks - ready for close inspection.