_Mrs. B._ The green leaves reflect both blue and yellow rays, which produce a green colour. They are now in a coloured ray, which they have a tendency to reflect; they, therefore, reflect more of the blue rays than the rose, (which naturally absorbs that colour,) and will, of course, appear of a brighter blue. _Emily._ Yet, in passing the rose through the different colours of the spectrum, the flower takes them more readily than the leaves. _Mrs. B._ Because the flower is of a paler hue. Bodies which reflect all the rays, are white; those which absorb them all, are black: between these extremes, bodies appear lighter or darker, in proportion to the quantity of rays they reflect or absorb. This rose is of a pale red; it approaches nearer to white than to black, and therefore, reflects rays, more abundantly than it absorbs them. _Emily._ But if a rose has so strong a tendency to reflect rays, I should imagine that it would be of a deep red colour. _Mrs. B._ I mean to say, that it has a general tendency to reflect rays. Pale coloured bodies, reflect all the coloured rays to a certain degree, their paleness, being an approach towards whiteness: but they reflect one colour more than the rest: this predominates over the white, and determines the colour of the body. Since, then, bodies of a pale colour, in some degree reflect all the rays of light, in passing through the various colours of the spectrum, they will reflect them all, with tolerable brilliancy; but will appear most vivid, in the ray of their natural colour. The green leaves, on the contrary, are of a dark colour, bearing a stronger resemblance to black, than to white; they have, therefore, a greater tendency to absorb, than to reflect rays; and reflecting very few of any, but the blue, and yellow rays, they will appear dingy, in passing through the other colours of the spectrum. _Caroline._ They must, however, reflect great quantities of the green rays, to produce so deep a colour. _Mrs. B._ Deepness or darkness of colour, proceeds rather from a deficiency, than an abundance of reflected rays. Remember, that if bodies reflected none of the rays, they would be black; and if a body reflects only a few green rays, it will appear of a dark green; it is the brightness, and intensity of the colour, which show that a great quantity of rays are reflected. _Emily._ A white body, then, which reflects all the rays, will appear equally bright in all the colours of the spectrum. _Mrs. B._ Certainly. And this is easily proved by passing a sheet of white paper, through the rays of the spectrum. White, you perceive, results from a body reflecting all the rays which fall upon it; black, is produced, when they are all absorbed; and colour, arises from a body possessing the power to decompose the solar ray, by absorbing some parts, and reflecting others. _Caroline._ What is the reason that articles which are blue, often appear green, by candle-light?