lens. The room is darkened, and the light coming from without is brought to a focus on the inside of the flask. A hole has been made through the glass, and as the water streams out the light is totally
Fig. 8.—The Fountain of Fire.
reflected so as to illuminate the stream as it falls into the pail below. Of this experiment the authors say:
"How magical! The curving stream of water is full of light, and appears like a stream of molten iron. The spot where it falls seems touched with fire. Put your finger in the stream of water, and it is brightly illuminated. Of course, the water soon runs down, and the display stops. To prevent this, bring water in a rubber tube from the water-pipes in the house, and then regulate the supply so that the receiver may be kepi full as fast as the water runs out.
"Place a piece of red glass behind the flask in the beam of sunlight, and the stream of water will look like blood. Touch it, and the hand will be crimson, and the scattered drops that fall in a shower into the tub will shine like drops of red fire. Place a green or blue glass behind the flask, and the stream of water will turn green or blue, and present a most singular appearance. Hold a goblet in the stream, and it will overflow with liquid light. Flashes and sparkles of fire will appear in it, and foam over the sides, shining with brilliant light.
"This beautiful experiment is as interesting as it is strange and magical, and it illustrates both refraction and total reflection. The flask makes a lens, and the falling stream of water is lighted up by the cone of light that enters it at the hole in the flask. Both the water and the light pass out of the hole together,
