VTG ANTIQUE Folding Fuel Tank Depth Measuring Yard Stick Ruler Farm Garage Tool

Description

Cleaning out the old barn. Found this up on a rafter. Looks to be in excellent vintage condition.
Was it used by a carpenter? A Surveyor?
To measure the depth of oil or gas?
(Seems likely)
Perhaps to measure horses or cattle? It's an interesting item. Three sections - two are marked with inches - total about 9 feet. Solid construction. Probably dates back to the turn of the last century or earlier.
The barn is from the 1830s to 1850s. Sold as is.