As a follow on to Jack Comer's nice collection of photos, here's a picture of one found in Wyoming recently. It has Edison / Battery Oil / Made in U.S.A. / Thomas A. Edison / Incorporated / Bloomfield, N.J. / U.S.A. embossed on the front and his cursive signature on the back. The bottom has a 3 P (inside a circle) 201. The older 'flask' type bottles were produced in the Orange, NJ facility from 1908 (the earliest patent date of the battery) until 1915 when there was a fire and the Orange facility burned down. Production of the battery oil bottles was moved to Bloomfield after the fire. The Bloomfiled embossing indicates that the bottle is circa 1916 or newer. The oil was added to Edison Primary Batteries on top of the caustic soda and water electrolytic solution to help prevent evaporation. The batteries were used to energize track and signal circuits and required periodic maintenance. That's why they are found by insulator collectors following abandoned signal lines.