This recalls Hamlet’s dressing in black and continuing to mourn his father’s death long after the court had stopped (1.2).

At the time the length of mourning (the wearing of black suit and limited social life) would’ve been a year and a day. Stephen is extending it. It is important to note the allusion to Hamlet. Later in Telemachus, Mulligan will state, “It is quite simple. He proves by algebra that Hamlet’s grandson is Shakespeare’s grandfather and that he himself is the ghost of his own father.” Joyce parallels again Christ’s life to Shakespeare to his own biography.

The military command to dismisses troops. The Martello Towers housed up to 16 soldiers in the round room.

In Greek mythology the hyperboreans were a mythical people who lived far to the north of Thrace. Also used by Friedrich Nietzsche to describe the Ubermensch or Superman.

Hyperborea was also held by the ancient Greeks to be Apollo’s winter home, where he was venerated among its people. Also noting that Apollo was recognized as the God of truth, prophecy, and light (among other things), this furthers Mulligan’s character by aligning it with said aspects. (see §2 for Apollo’s association with Hyperborea)

The Mast of a sailing vessel is a tall spar, or arrangement of spars, erected more or less vertically on the center-line of a ship or boat. Its purposes include carrying sail, spars, and derricks, and giving necessary height to a navigation light, look-out position, signal yard, control position, radio aerial or signal lamp.

Rockaway Beach is a neighborhood on the Rockaway Peninsula in the New York City borough of Queens. It is located on the South Shore of Long Island.

Feelings of anger and irritability were once thought to be derived from the spleen. Example: “to vent one’s spleen.” Ishmael goes to sea to keep himself level-headed.

Anatomically, spleen is involved in the production and removal of blood cells in vertebrates. Melville is, thus, referring to the scientific purpose as well as literary meaning of spleen here.