Early in the morning about 4am on 22nd April 1861 the work to rig the cable connecting the electric clock designed to fire the time gun and the Nelson Monument began. The rigging was supervised by Robert Stirling Newall the manufacturer of the cable. The drum holding the cable was set up on a wooden frame inside the watch tower standing between the Argyle Battery and the Mons Meg Battery. Using a windlass and gearing a rope attached to the end of the cable was lowered by the riggers down to West Princes Street Gardens. Professor Piazzi Smyth and Frederick James Ritchie were at the fortress to observe the operation. Image credit ‘Old and New Edinburgh’ by James Grant.