Tested and approved
by the Service Engineering
United Motors Service Ltd.
At first glance I thought this device might have been a tire gauge. The company name on the badge is United Motor Service, which was a company created in 1916 to market Delco, Klaxon and Remy products, This company a few years later became part of General Motors, but back to the tool!
There is a wire hook on one end connected to what seems to be a small scale- going up to 14 oz. So it is hooked onto something, the main body is held in the hand and spring tension is measured. Turns out this is a tool to measure the spring tension of ignition points! The tool dates back to the thirties, perhaps the points spring tension was adjustable back then? Apparently the polished oval on the back of the badge can be used as a mirror while setting the points. Instructions here.
Thanks Rick, for showing me this.