Melville is my reading focus lately and I came across Seelye's book in my College Library's shelves and grabbed it. In the opening pages, it seemed pedantic, but I am glad I persisted. The ironic diagram Seelye uses to teach Melville's books lies in the paring of a line with a circle. For example, Ahab's linear quest for the white whale contrasts with Ishmael's quixotic meanderings. One is the cartographer and the other the globe; one nails the circular doubloon to the mast with a straight nail near the equator and the other meditates on its multiple symbolic values.
As a pedagogic tool, the ironic diagram can be useful in reading and interpreting Melville's works.