When the sun shines perpendicularly a longitudes, then it is the mid – day time at twelve o’clock in the places located on that line. According to them, the time that the clock keeps at mid-day, then the sun will not be vertical. It will be tilted away from this position because the speed of the sun does not always remain the same. Due to this variation (decrease – increase), Solar – Day is not convenient for time measurements. Solar – clock is used to know the time through the sun. According to the condition of the sun, we have to take the trouble to keep the time in its accordance, because the clock needles need to be moved forward or backward every day, according to the sun.
