THE RAINBOW. "J^ 



Versity of colours which we so much admire, for the purpose 

 of beautifying the scene, and rendering it a source of plea- 

 sureable enjoyment. It is an ornament which embellishes 

 nature wherever we behold her. 



Questions. — 1. Of what was Sir Isaac Newton the first disco- 

 verer ? 2. How may a white ray of light be separated into the va- 

 rious colours of which it is composed ? 3. How arc the colours 

 divided, and what are they called -* 4. How is the idea, of whiteness 

 produced ? — What is the proof of this .'' 5. How may a substitute 

 lor a solid glass prism be made ? 6. How is it proved that the colours 

 which seem to proceed from coloured bodies do not belong to those 

 bodies .' 7. What are colours .' 8. Wliat is a spectrum ? 9. Describe 

 fig. 37. 



LESSON 35. 



JVie Rainhoio, Halo, and Parhelia. 



Parhe'lia, (singular, Parhe'lion) a bright light appearing on o»e 

 side of the sun. 



When the rays of tlie sun strike upon drops of water fall- 

 ing from the clouds, and we are placed in such a direction 

 that our back is towards the sun, and the clouds before us, 

 we observe a peculiar phenomenon in the heavens, called a 

 rainbow. We may consider the drops of rain as transparent 

 globules upon which the rays fall, and are twice refracted 

 and once reflected. Hence proceed the different colours of 

 the rainbow. These colours appear the more vivid, as the 

 clouds which are behind are darker, and the drops of rain 

 fall closer. The drops continually forming produce a nevB^ 

 rainbow every moment, and as each spectator observes it 

 from a particular situation, it happens that scarcely two men, 

 strictly speaking, see the same rainbow ; and this appear 

 ance can only last whilst the drops which fall are succeeded 

 by others. 



Triumphal arch, that fdl'st the sky 

 When storms prepare to part,' 



I ask not proud philosophy 

 To teach me what thou art — 



Still seen, as to my childhood's sight, 



A midway station given 

 For happy spirits to alight 



Betwixt the earth and heaven. 



