one is sure when the first sundial was constructed.
The Egyptians about 1500BC constructed step Sundials and some of
them accounted for even the change in the length of the day About
four hundred years ago on salisbury plains is a monument called
the Stonehenge which traces the movement of the sun over an year.
In 1728 Jantar Mantar, an astronomical observatory was built in
the city of Jaipur, India. It has a sundial with a 30 metre high
gnomon. Before the modern clock, people often carved sundials into
buildings. In many historic farmhouses, one can often find a line
carved into something like the window sill, a wall, or a floor.
This mark was called the noon mark, and was used to indicate the
time of local noon.
In modern times, the need for sundials has diminished. Thanks to
accurate digital watches, there is no need to carry around a pocket-sized
sundial. Nevertheless, sundials should not be forgotten. They are
still one of the most reliable forms of timepieces available, for
the sun will always rise in the morning and set in the evening.
The length of the winter days will always be shorter than the length
of summer days. If we get nothing more than pleasure out of their
use, we at least gain a clear understanding of sun and its motion
through the sky.