Here's a thing that a mate of mine was showing me recently.
I have no idea how it got over to here in New Zealand.
It's a:
Radio Protector Model No. R-73, Manufactured by Cook Electric Co, Chicago.







How would one of these have been used?.

The same way as a telephone protector.
One lead is earthed, one to aerial.

Thanks classicsat!.
I was just trying to work out what the objects
to the left of the knife switch were.
I'm merely guessing that the long cylindrical thing is some sort of a Discharge tube or a fuse?.
Anyone seen one of these before?.

You are correct: the thin cylinder is a fuse, and the can contains a spark-gap lightning arrestor. The aerial connects to the upper fuse end, the radio to the upper switch contact, and ground to the lower switch contact.

The switch was used to 'earth' the aerial whenever the radio wasn't in use, and especially during a storm, to bypass any high voltage to ground. Note that the switch blade's only contact is to the fuse bottom end, inside the porcelain.

Trumpy,

It looks like the old telecom lightning arrestor when you have an overhead phoneline, those had two fuse elements, the same size as that fuse or tube shown on your photo.

I will post a photo.

Cheers

Ray