Calendario con Bussola, Brunito
An early, simple pocket calculator from an era when 40-50 years were akin to perpetual. Its origin goes back some 500 years. Calculate the day of the week for any given future date, within a 40-year or 50-year span. To use, simply rotate dial until the selected year lines up with the selected month. Locate the particular date and find the day of the week above it.