Hey there Betty! We consulted with a whisky / distillery expert who told us this: "If it has a sliding brass gauge that moves up and down the rod freely then it’s called a “dip stick” and used for measuring the quantity of whisky in a cask. It should be square and each side has markings for the different sizes of casks, i.e. the mark for 26 gallons will be at different levels on each side."
Of course, if you can provide a photo, that would be very helpful.