Calendario con Bussola

Calendario con Bussola.

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.
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