"I was upon the platform two hours this afternoon, looking at her"
Old Portsmouth cannon
Creative Commons AttributionOld Portsmouth cannon - Credit: Toby Irvine

 A reference to the Saluting Platform, a coastal battery (a fortified location where heavy guns are placed) situated on the Grand Parade, Portsmouth. Built around 1522, it got its name because the guns stationed on it were fired to greet ships entering the harbour, a practice known as saluting.

Click here to see a picture of the Saluting Platform in the reign of Queen Anne.