Here is a vintage catalog listing for an educational dial. The dial is a child’s clock that was 12″ in diameter, printed on thick cardboard, and was provided with movable steel hands. The numbers on the clock are Roman Numerals. The price of the clock was 25 cents in 1913. The ad is from the Northern School Supply Company Catalog, published in 1913. Here is a black and white clip art version of the clock from the ad. And another version of the clock without the hands. Click on images to enlarge.