The meridian of any place is the line on which the sun casts a shadow at mid-day. If the line were continued in both directions it would pass through the north and south poles. Set up a stick, and measure the length of its shadow at 9.30 in the morning. Say it is 3 feet. With a piece of string 3 feet long and the stick as center,
describe a circle.
At 2.30 in the afternoon it will be found that the shadow again just touches the reference of the circle on the other side of the stick. If lines be drawn from the foot of the stick to the two points where the shadow met the circle at 9.30 and 2.30, and the distance between the two halved, this will give the meridian of the place.