Protecting the pillars

I doubt if one person in a hundred has noticed, but at the foot of each of the four great pillars outside the General Post Office…

I doubt if one person in a hundred has noticed, but at the foot of each of the four great pillars outside the General Post Office there stands a bell-shaped object of metal.

A colleague called my attention to them yesterday, explaining that he was in the habit of propping up his bicycle against the outside one on the left, which thereby had been brought to his notice; but of their purpose he could tell me nothing, and neither could the friendly cop who was easing his back against the G.P.O. wall.

What are they for, these bell-shaped objects? My colleague had a bright-idea that they might be there to protect the pillars - presumably from the assaults of infuriated car-drivers, but I find this hard to believe. Can anybody tells me?

The Irish Times, February 28th, 1940.