Newton's Cannon

Enlightened science is transformed into blackest magic in the opening volume of Keyes's (The Waterborn) 18th-century alternative history, The Age of Unreason. Sir Isaac Newton turns alchemist to obtain Philosopher's Mercury, the key to cosmic end-of-the-world weaponry. Stolen by a philosopher-mage of France's King Louis XIV to use against the invading English, the hellish device threatens to obliterate London unless two unlikely young geniuses can defuse it. Alternating chapters trace the pair's discrete stories, as American icon Ben Franklin, here portrayed as a randy adolescent, and the toothsome Adrienne de Montchevreuil, Louis's latest mistress, separately wield fearsome theorems against supernatural forces manipulating humanity. Clearly enamored with the glories of Versailles, Keyes writes passages of swordplay and foreplay that fitfully flare into life, but the novel is ultimately foiled by muddy secondary characterizations and a finale that fizzles. (May)