What Mary Kay Phelan does best, to undergird a given situation (Four Days in Philadelphia, etc.) and furnish authentic detail, gives substance but no energy to her account of the long struggle to start and complete the Erie Canal. Given the extent of the opposition, the many delays and debates, it is not until page 43 that the first spade of earth is turned--and even then the action is fitful. Construction is repeatedly interrupted by political intrigue, all described in the same even tone, and curiosity is constantly frustrated by the book's mode of illustration--an occasional woodcut rather than the graphic evidence that, say, an American Heritage entry would provide. When the first flotilla navigates the length of the canal for the celebrated Wedding of the Waters, the chronicle finally comes to life, rather too late to make a grand adventure out of this historical achievement. But those more interested in learning than in reliving will find the book a dependable (and excellently indexed) source.