126 THE RAINBOW. 



parcel of it through a triangular prism of glass, 

 which gives in a smaller space, and therefore with 

 greater brightness and perfection, all the colours 

 which are seen in the rainbow, and which on a 

 very dark cloud, opposite to the sun when nearly 

 setting, is almost half a circle and very beautiful, 

 is found to have other properties than its bright 

 colours. These cannot be found in the rainbow, 

 for that recedes as we approach it ; and though the 

 rain- drops on the verdure sometimes bring it ap- 

 parently to our very feet, all our speed cannot 

 come up with it. We may. follow it into the 

 'cloud, but we cannot gain upon it ; and though 

 the cloud seems dark before us, the passage of the 

 sunbeams is so easy that we can follow the bow 

 till we lose it ; and " chasing the rainbow through 

 the shower" is (or once was) a summer amuse- 

 ment with the hind-boys on the moors, who 

 took to the observation of Nature, because they 

 had few other amusements. 



When the little bit of bright rainbow, or spec- 

 trum as it is called, is examined, it is found that 

 the beam of light is bent out of its path, and 

 lengthened in the direction in which it is bent ; 

 and, the parts nearest and most distant from the 

 original direction of the light, which bound the 

 length, are the ends, and the intermediate bounda- 

 ries the sides. The colours lie across it from side 

 to side ; first red, at the nearest end, then yellow, 

 and then blue ; but from the red to the yellow 

 the colour passes through every imaginable shade 

 of orange ; from yellow to blue, it passes through 

 every shade of green ; and the blue fades off in 

 brightness till it vanishes in that soft purple which 

 often tints the clouds in the evening, and some- 



