284 COLOUR OF THE IMEDITERKANEAN^ 



have often come down to caress tlie beautiful ^-outh as 

 he rested upon tlie mountain of Latmos. How ungrate- 

 ful are we to those who, through weary research, have 

 thrown light upon the sources of light. O miserable 

 perversion of the human mind wliich loves to fill the 

 annals of history with accounts of bloody deeds and 

 to mislead the ingenuous minds of )'outh with these 

 narratives !" 



CHAPTER V. 



The full moon had slrone clear and brioht the whole 

 night through, but next morning clouds came up from 

 the east, and soon the whole sk^- was overcast and grey. 

 Yet the Mediterranean remained blue, retaining its char- 

 acteristic tint. 



The Mediterranean owes the deep blue, ^hich we 

 so admire, to the transparency- and clearness of its waters. 

 Most masses of water are blue b^' transmitted light. 

 This is \\h\' the ice of crevasses and glacier caves 

 appears pure blue. If a sufficiently long tube, blackened 

 within, \\'ith a mirror fi.xed at its lower end, be sunk 

 perpendicularh" into the Mediterranean, we should see 

 the water in the tube shining like a sapphire. An object 

 appears coloured to us when it absorbs certain rays of 

 white light and reflects others. These reflected raAS, 

 when the^• reach our e\'e, create the impression of a certain 

 colour which we ascribe to the object. Water is blue 

 because it c|uickh' absorbs the red and yellow ra^'s of 

 white light and transmits onh' the blue. To create this 

 impression on our e\e the ra\-s which reach it must 



