The Greeks should be given credit for the calculation of time and geographical breadth on the basis of the sun’ s orbit, since they invented the clock. A look at a modern clock or wrist watch gives us not only the exact time but also tells us the day of the week and the date. The clocks that supply us with all this information are descendants of the solar clocks that the ancient Greeks used to set up in public areas. These clocks did not only indicate the time but also, approximately, the position of the day in the year. We are reminded here that the Greek word “‘ώρα”, means not only “season” but also “hour” in the modern sense of the word. However, the hour as a part of the day was calculated in a different manner by the ancient Greeks and coincides in duration with the 1l24 of the day only during the winter and the summer solstice.