Looking south from the O'Connell bridge in Lestrygonians, Bloom sees the four-story Ballast Office, which stood at the corner of Aston Quay where Westmoreland Street begins running south from the river. The building served as a reliable timekeeper for the City and the Port of Dublin. Over the front door, on the outside wall of the second story, perched a large clock known for accuracy. On the northeast corner of the building's roof a large copper ball descended every day at 1:00. Bloom sees that the ball has fallen: "After one. Timeball on the ballastoffice is down. Dunsink time." He is wrong about the Dunsink time, but he corrects his mistake later in the chapter.

JH 2016

Photograph of the Ballast Office, taken from the north (quayside) with the "timeball" seen mounted near the corner of the roof. Source: www.theatlantic.com.

Another image of the Ballast Office, from the National Photographic Archive of Ireland, this one taken on Westmoreland Street, showing the clock on the second floor wall and the copper ball on the roof. Source: homepage.eircom.net.

The Ballast Office in 1870, seen from the Carlisle Bridge in an engraving by Samuel Frederick Brocas and Henry Brocas held in the National Library of Ireland. Although the perspective is close to Bloom's, the time ball had not yet been constructed. Source: dublinportblog.com.