Acquired three of these in an auction, amongst other stuff. They have vinyl cases which come with gold writing on the front "M. H. Mear & Co., 56, Nettleton Road, Dalton, Huddersfield."
They are of the circular slide rule type, white plastic and are in good condition. "Glare Index Calculator", "Electric Wiring Calculator" and "Feet and Inches to Millimeters converter."
Question is, are they worth anything? Figured people here might know a bit about them as many here are builders, electricians, etc.
Thanks for any input.
Marcus