Kellogg’s Wheel of Knowledge Facts About the United States Copyright 1931 A. Knapp This nifty wheel was a company promotion in the 1930's, providing information about the 48 "continental" states! Turn the wheel to get facts about each U.S. state, including population, capital city, square miles, major river, time zone and more. Also called a "volvelle", this one measures approximately 6 1/2 inches square. Cereals advertised includ...e: Corn Flakes, Rice Krispies, All-Bran, PEP Bran Flakes. There is some wear around the edges, particularly to the corners, but still a unique piece! Please see our other items, and check with us about combine shipping.Contact us with questions after viewing photos, and thanks for looking!