Lang & Jacobs
Directory of American Toolmakers Information
The found marked tools are both cooper's hoop drivers. The "Jaco" in the mark is inconsistent with that depicted in the catalog.
LANG & JACOB/BOSTON,MASS
Nelson, Robert E., Ed. (1999). Directory of American Toolmakers: A listing of identified makers of tools who worked in Canada and the United States before 1900. Early American Industries Association.
Lang & Jacobs. (1884). Catalogue and price list of Lang & Jacobs’ head quarters for coopers’ supplies & cooperage stock, Boston, Mass. Coopers’ tools & truss hoops a specialty. Facsimile of the original. Long Island, NY. The Early Trades and Crafts Society.
http://www.mwtca.org/OTC/ar000021.htm -- Article in The Gristmill including notes on C.E. Jennings