why does melville/ishmael delay the entrance of ahab until the third paragraph

Ahab finally receives an introduction in this chapter after a long period of foreshadowing by Melville. In contrast to the portrayals of the other ship officers by Melville, the description of Ahab focuses on the qualities that are inhuman and even mechanical. There are few details akin to those given for Stubb or Starbuck, which emphasize their personalities and ideals; instead, Melville gives a basic physical description of Ahab that compares him to largely inhuman and inanimate objects. The basic impression that Melville gives of Ahab is one of durability; Ahab is a man who shows few basic human characteristics, but instead has been chiseled and formed by his whaling experiences. His ivory leg is a significant aspect of his character, demonstrating both this somewhat inhuman quality to Ahab as well as showing that the whale is an inseparable part of Ahab himself, literally part of his body.