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Show 252 LIGHT. run of several thousand miles. So that those minor operations of these internal . fires o~. the earth are necessary to account for the 1nequahtles of the surface, which are not formed of rock but of accumu lated fragments. . They also enable us to account for the formatiOn of beds of chalk, and shelly limestone, and marble in all then varieties of form. SECTION VIII. Observation of organized Beings. IN the former sections, an attempt has be.en made to call the attention of the reader to the obJects and phenomena of the creation ar:ound him, in their g.eneral appearances and propert~es as matter, an~ ~t~hout any reference to the particular forms of mdtvid-ual subjects. . Light is nearly the same wherever tt may fall, or from whatever it may be produced; and tho~gh the light which comes to us from o~e sub~tance ts often very different, in colour and mtensi~Y, from that which comes from another, the portwn that d<?es come to our eyes is still a part of the s?-me specific light, which is entire and undecomposed m the beams of the sun. When the fields send us back the green, and, as we suppose, drink up the red, that red 'Yh~lly disappears in the leaves and the grass ; and, m hke manner, when any other colour is given out to us, the remainder is absorbed, and we cannot, by any . scrutiny in which we can ~ng~ge, fi~d out what becomes of the portion whiCh 1s retamed by any substance, or how it affects the other properties o( that substance. . · . · As we can, by means of the prism, decompose the LIGHT MERELY VISIBLE. 253 sunbeams into all the tints that are necessary or even possible in the colouring of nature, we can have no reason to doubt that the colours of nature are all produced by the sunbeams. But, in consequence of the great rapidity with which light moves, we must not confound the manner in which we see painters make up their shades of _colour by mixi~g variously coloured substances, with the mode m which the colours of nature are produced. The light 'reveals the colours, but we are not warranted in saying that it makes them ? for though, by means of a common triangular pnsm, we decompose a beam of licrht into the most perfect spectrum, and keep that ~pectrum ever so long on the identical piece of white paper, or any other surface, whatever may be its colour, we shall never be able to find a trace of the spectrum on the paper, or other surface, after we remove it out of the light which the prism · decomposes. Now it is evident that, if the remaining colours of the sunbeams did not in some way act upon the surface, which gives out any particular colour, the ~urface that shows any colour under the spectrum would show the same whether the spectrum were there or not, and as the same colour remains on the surface after the spectrum has been removed that was there before the spectrum was thrown upon it, it is just as evident that every coloured surface must have some peculiar state or property which disposes it to show its particular colour. Hence it is evident that colour, and that which we usually call light, is not a being or thing of any kind, but merely a relation between one surface and a reflection from another surface ; that being the case, we cannot regard light as in any way forming a part of, or otherwise affecting, the quantity of matter in bodies ; and, therefore, all such speculations as, "whether the quantity of matter in the sun be di.minished in consequence of the light which the sun y |