Let us follow the railroad tracks out on the plain where there is level land in all directions as far as we can see. All around us we can see the sky meeting the distant plain in a long even line. This is called the horizon.

The ideal example of the horizon is seen when viewed across a large body of water where no distant shore is seen. At sea the horizon is one continuous line.

We may consider the horizon as continuous. This is true though the view may be obstructed by an object: a hand, a building, or a mountain. The horizon is still there though we go into the building and close the door. If objects became transparent the horizon could always be seen. This is illustrated on the opposite page.

THE VANISHING POINT

Now we stand between the two shiny rails and look along the track. These rails go on and on across the level plain until they reach the horizon where they are lost from sight in the distance.

We call the place where they disappear the vanishing point.

THE EYE-LEVEL

Now look down at your feet. There you see the track. Raise your eyes and look fifty feet beyond. You still see the track although you are not looking directly down upon it.

Then look straight ahead. You see the track as it climbs to a height level with your eyes and disappears at the horizon in the distance. This height can be called the eye-level.

Here the horizon and the eye-level become one and the same thing.

THE HORIZON AND THE EYE-LEVEL

Now sit down on the track and look about. You will find that your eye-level has lowered. The distant horizon also appears lower in order to meet this change of eye-level.

If we ascend in an airplane we shall find that the distant horizon rises with our height. It appears to remain at eye-level.

This accounts for the peculiar basin-like appearance of the earth when viewed from a great height.

We can now understand why the drawing of the corner of a room looks different when sketched from a low stool as compared with one sketched from the top of a stepladder.

The height of the eyes becomes a very important factor in freehand drawing.