The Rainbow. 207 



find, that when the eyes are very weak they can 

 scarcely support a scarlet colour; its impres- 

 sions are too powerful, and, next to the solar 

 beam itself, dazzle and disturb the organ. On 

 the contrary, the more refrangible the rays (the 

 violet for instance), the less forcibly they strike 

 the eye; and green, the intermediate colour, 

 is the most agreeable, and is that in which 

 Providence has chosen to array the meadows 

 and the woods, in a delightful variety, the di- 

 versities of green being greater than those of any 

 other colour. 



Of all the objects of nature the rainbow ex- 

 hibits the prismatic colours in the greatest per- 

 fection. It is, indeed, a natural prism, and 

 separates the component particles of light with 

 the same accuracy and precision. 



The rainbow was one of those phsenomena 

 which astonished and perplexed the antients; 

 and, after many absurd and unsuccessful con- 

 jectures, their best philosophers, Pliny and 

 Plutarch, relinquished the inquiry as one which 

 was above the reach of human investigation. In 

 the year 1611 Antonio de Dominis made a con- 

 siderable advance, however, to the true theory, 

 by suspending a glass globe in the sun's light, 

 when he found that, while he stood with his 

 back to the sun, the colours of the rainbow 

 were reflected to his eye in succession by the 

 globe, as it was moved higher or lower. He 

 was, however, unable to account for the pro- 



