Having thus broken up the beam of light, Newton, by means of two prisms, put together again the rays which he had separated, and the sunbeam was "white" as before. Perhaps you wonder why we do not always see coloured light: the reason is that the waves of light, unless interfered with and turned out of their straight path, all travel together in their rapid, noiseless course, and so remain unbroken. You will find it very interesting to make the first of Newton's experiments yourself, and some day perhaps you will hear what wonderful things about the sun and the stars are being learnt in our own time by means of the spectroscope, which is an instrument having a fine slit through which the ray is passed before it is allowed to fall upon the prism. And now what do we mean when we talk of things being of different colours? When we say of snow that it is white we mean that, as the light falls upon the snow, it is all sent back again. The surface of the snow reflects all the light, and keeps none. The other day, when I was buying some flowers to plant in the garden, the woman who was selling them showed me a black pansy. "I am sure you would like to have this root," she said, "black pansies are so rare." [Illustration] I did not buy the flower, for I did not think it nearly so pretty as the purple and yellow pansies, which seemed to look up at me with such knowing little faces; but I was interested to see it, because (and are you not glad that it is so?) black flowers are very rare. But why was this pansy black? Ah! it was quite different from the snow; it kept all the light which fell upon it, and gave away none. You see that God has given to some things the power of absorbing light and to others that of reflecting it. If it were not so, our world would be very different from the beautiful world which it is--as different as an engraving is from a coloured picture, with fields, gardens, sea and sky all of varied hue. Almost all the flowers are so beautiful because, while they keep some of the colours from the light which falls upon them, they do not keep all. Now look at the flowers in that glass upon the table. The lovely rose keeps part of its ray of light, but gives us back the red; the larkspur gives back the blue; and those pure white lilies, which show so fair beside the roses, give back all the light in its bright whiteness just as it comes to them, so that a poet, who loved them well, calls them "those flowers made of light." And the water in the glass, why is it white? Because water is what is called transparent; it does not drink in the light, but lets the whole ray pass through it, as it passes through the window-pane.