It seems that Mary Dunbar was the name given to the Jewel Tea Co.'s spokesperson in the 1920's. The lady who went by that company name was the head of the company's test kitchen, and wrote a series of cookbooks and a monthly newsletter. She is credited with the invention of the 7 minute icing recipe. There was even a Mary Dunbar seal of approval, much like the Good Housekeeping seal of today.
It seems that the Jewel Tea Co. put coupons in with their various spices and tea products, and those coupons could be redeemed for various household goods. The most well known of these was the Hall China Co. Autumn Leaf pattern china and related items. This pattern in highly collectible today. Our loaf pan was probably one of those premium items.
We have this Mary Dunbar pan listed on eBay now, if you're interested.
Premium items used to be so common. Banks gave you clocks and toasters for joining, and Service Stations gave out knives with fill-ups. I'm sure you can think of a lot more such give-aways. The customer was KING in those days. Now you're lucky if you get a pen with the company name on it, or a refrigerator magnet!!
Hmmmmmm .... something's changed over the years, hasn't it?? Now, it seems as if the mentality of most businesses and clerks is that they are doing us a favor by deigning to do business with us. I liked it better the way it used to be, thank you very much!!