How may these colors be separated?
By a prism, or three-sided piece of glass.
How may this be done?
If a sunbeam, shining through a hole in the window-shutter of a dark room, should fall upon a prism, it will be broken up as it passes through the prism, and be shown on the opposite wall, in the seven rainbow colors.
Fig. 6.
In [Fig. 6], D is a sunbeam passing through a shutter. When it passes through the prism, at E, it is separated into the seven rainbow colors, as is shown on the opposite wall.
In what order will these colors appear?
They will always appear one above the other, in the order named.
How may this order be remembered?