Along with the Battery lids I have a small collection of Battery oil bottles. This oil was poured into the top of the storage cell to keep the battery acid water from evaporating. Since water and oil don't mix it would create a layer to protect the acid. Strangely enough, I've only found a few manufacturers that had oil bottles with Edison being the most. Here is a picture of the first Edison Special Battery Oil bottles Orange NJ. This is the round type in Lt. blue glass. Even rarer is the Australian marked and the lavender glass ones. Pictured here is the 4oz., 6oz, and 3oz. The 4 ounce bottle is the only one with a mark on the bottom of C-4. I'm assuming these were made by Hemingray because of the later style bottles that were numerouly made by Owens-Illinois but correct me if I'm wrong.