This is an antique multi-purpose lever ratchet jack, from the Wm. E. Pratt Mfg. Company in Chicago, IL.
This jack is from the early 1900's, and its design was motivated by the need for car jacks. Most of the early jacks tend to be of the screw design. This jack is lift notch design which was a design that typically could handle larger weights.
At lowered state, this jack is 10.5" and will lift 6" higher. The base is 7" x 3".
This jack is in good pre-owned condition, and still works well.