Seemed a bit weird to me...but I guess in those days...it wasnt!

Yes it does look a little strange.. Can you rip it of and send it to me? (JK) ;o] I hope someone here nows what its for (is) and will tell us.

yes, it's a little stange this one....

This is a 1927 Morris Chump, So the chap in the garage told me. It’s in a vintage car restorer near Edinburgh; I can pass the chaps details on, when I find them, if you like. I’m sure he will know everything you want to know, he told me loads but it was month’s age and I can’t remember everything he said, but he restored this one himself.

Blessed Be,

Zachary

These can still be bought today.  We put one on a 1933 International Pickup that we restored.  It is sort of akin to a thermostat and you can tell if things are getting too hot.  Your image shows a fancier one that we bought.  I don't remember if we got it from the antique cars parts supply in OKCity or ordered it from the Hemmings Magazine.  But they were quite common in that era.