CONVERSATION XVI.
ON REFRACTION AND COLOURS.
TRANSMISSION OF LIGHT BY TRANSPARENT BODIES. REFRACTION. REFRACTION BY THE ATMOSPHERE. REFRACTION BY A LENS. REFRACTION BY THE PRISM. OF COLOUR FROM THE RAYS OF LIGHT. OF THE COLOURS OF BODIES.
MRS. B.
The refraction of light will furnish the subject of to-day's lesson.
Caroline. That is a property of which I have not the faintest idea.
Mrs. B. It is the effect which transparent mediums produce on light in its passage through them. Opaque bodies, you know, reflect the rays, and transparent bodies transmit them; but it is found, that if a ray, in passing from one medium, into another of different density, fall obliquely, it is turned out of its course. The ray of light is then said to be refracted.
Caroline. It must then be acted on by some new power, otherwise it would not deviate from its first direction.
Mrs. B. The power which causes the deviation of the ray, appears to be the attraction of the denser medium. Let us suppose the two mediums to be air, and water; if a ray of light passes from air, into water, it is more strongly attracted by the latter, on account of its superior density.
Emily. In what direction does the water attract the ray?