I have an old undated photo of my grandfather Thomas James (Jim) McCall standing beside a truck with Florence-Mayo decal on the door.
My Dad, Mack Ray Haddock used this type FM curer we referred to as a gun fired furnace. It worked great and really helped in taking out the tobacco as you could remove the heat diffusers and place them in the corner of the barn giving a much larger work area.
This is either a prototype or early production version of F-M's "Jet" curer. The final version had 8 rectangular duct heat spreaders instead of the 4 shown here. The round tube leads to an oil burner identical to one used in a home furnace and burned #2 fuel oil. It was controlled by a thermostat so curing was unaffected by ambient air temperatures or winds. It also had a "clock thermostat" which could be set to increase barn temperature a predetermined number of degrees per hour. Very reliable but did require electrical service which a lot of older barns in remote locations didn't have.
I found an old yard stick that said, Florence-Mayo Numay Co. Gave the address as Farmville, NC. Phone # 3165