The first image is a painting of a pedestian bridge that connected George's Dock gate to St Nicholas' Church. It's most distinctive feature was the red 'time ball' fixed on its stair half-landing.

George's Dock gate, with St Nicholas's Church & Tower Buildings in the background, by Herdman, 1865 or later (below):

Time balls, like the one at Greenwich, drop at 1:00pm every day to enable ship's captains to set their clocks to GMT. 1:00pm was selected over 12:00 noon, because maritime astronomers were too busy taking their measurements at mid-day. Ships sailing on the day from George's Dock would need to keep watch on the ball, waiting for it to drop, to synchronize their chronometers (ship's clock) to GMT. This was eventually replaced by the 1:00 o'clock gun which could be heard all around the port (and city) as many here will still remember.

George's Dock Basin, 1871 (below):

Liverpool Panorama, 1865 (below):