Large Oval Ribbed-Top Tin Container- What is It?

When I purchased this large painted tin at a recent indoor garage sale, it was full of antique "muffs" and other furry things. I passed on the flea-bitten contents but I was quite intrigued on what the original use would have been, so it came home with me. I looked all over the internet for a similar one but could only find copper boilers and tubs. This tin-based handled oval container measures 18" by 15" and 12" tall. It has a central rib all around, a graduated ribbed cover and a lock and key that is functional. The outside has a thick peeling copper paint finish and the inside is painted with a blue enamelled colour. The contents of the house were all brought to Canada from England and were being sold by people who had no idea what they were selling so were not helpful in identifying it. I will upload other items from this sale that were equally quite interesting. What exactly was this used for 100 years ago?