Late 19th century educational tool for teaching children the four basic rules of arithmetic, devised by Father Charier, former student of the École Supérieure et Industrielle de la ville de Metz, formed as two octagonal stiff cardboard disks joined at the center, the top disk divided into four sections, one each for addition, subtraction, multiplication, and division, each section with two cut-out windows revealing the disk below, and illustrated with images of children doing math, with one small wooden handle for ease of rotating the disk, the bottom disk of red stiff cardboard and printed with numbers. Instructions for usage of the disk are printed to the underside. Some very minor soiling, small areas of edgewear to paper on top disk, overall very good condition. Approx. 15 inches wide. Loose as issued. La Flèche, France (Charier-Beulay) n.d. (circa 1890s).
This item functions as follows: the large cut-out window in each section corresponds to the calculation operation being performed, and can display numbers from 1 through 10. Above each of these windows is printed a bar with numbers from 1 through 10. The child chooses the number to display in the large window and aligns it with one of the numbers printed on the bar on the top disk. The result will appear in the small cut-out window at the top of the section. (For example, having the digit "4" show up in the large Multiplication window and align with the "5" on the printed bar will result in "20" showing up in the small window, to make 4x5=20.) The resulting numbers that appear in the small division window include decimals calculated to three places. Very scarce; as of July 2019, WorldCat locates a single holding in a North American institution. Book ID: 50050