First of a new fantasy series: In this alternate 1715, both science and alchemy work; young Ben Franklin, apprenticed to his printer brother James in Boston, begins to study the various alchemical devices--lights, weapons, faxes, and so on--that Isaac Newton has invented. Ben accidentally intercepts a communication on the ""aether-schreiber"" and helps solve the mathematical problem posed therein by an unknown scientist. Soon, however, Ben's being haunted by a weird, insubstantial demon that demands he cease his researches. Britain and France, meanwhile, fight a war using alchemical weapons. In France, Louis XIV, having taken an immortality serum and survived an assassination attempt, has been taken over by a demon, or malakus, like Ben's. Nicolas Fatio de Duillier, a vengeful ex-student of Newton's, uses Ben's formula to alchemically attract a comet from space towards London. Scientific genius Adrienne de Montchevreuil, forced to become the king's mistress, and helped by a secret society of women, labors to discover what Fatio has done. Ben, threatened by his malakus, flees to London to warn Newton; the latter, preoccupied with unmasking a traitor, can't stop or divert the comet. London is annihilated after a hasty evacuation, Ben becomes Newton's apprentice, and Louis's malakus moves on to beguile Czar Peter of Russia. Keyes's yam (The Blackgod, 1997, etc.) is colorful, intriguing, and well handled, if somewhat difficult to swallow: It's hard to see how alchemy and science could both work.