Originally posted by Racer X 69 The style is certainly the same. But gauge on this thing is only two and a half inches in diameter, not six.
I like the idea that it has something to do with pasteurization though, considering I found it in a barn where dairy operations once happened.
By Jove, I think you've got it! When pasteurization began, it was done by heating up large quantities of milk in a sort of vat or cauldron. That gizmo is the equivalent of a candy thermometer, or for a roast, or for checking the deep fat fryer temperature. The outer frame is a sort of spring, and as it flexes, it increases or decreases pressure on the side of the gauge, which probably has a plunger actuator below the extension that's screwed down to it. What's missing between the two parts that look like Frankenstein's electrodes is probably sort of bimetallic spring. The screw adjuster on the right calibrates the bimetallic spring, that being counter-tensioned against the springiness of the frame. Holding the grip on the bottom, one would dip the upper part including the bimetallic spring (or something else that expands and contracts in a regular way) and read the temperature on the gauge, so you'd know when the pasteurization was complete.
How's that for a theory?
This is a lot like "History Detectives", "Ask This Old House", and "Antiques Road Show", all rolled into one.