- The hour
- The month
- Day of the month
- The position of the sun in the ecliptic
- The twelve signs of the zodiac
- The number of days that have elapsed since the beginning of the year
- The phases of the moon
- It's age in days
- The hour in which it crosses the meridian which means that it tells the time of high time in London
Since Henry VIII often used to travel by barge to Hampton Court Palace it was practical to know when it was high tide and thereby the best time to travel by.
The earth is centred in the middle of the clock because the clock was made before Copernicus and Galileo began to doubt the heliocentric world-image (where the sun is the centre of the universe). The minor circle is the sun that was said to circle around the earth at the time.