vi INQUIRY AND INTERPRETATION 155 



homogeneous but consists of rays which are refracted 

 or bent by different amounts when they pass through 

 a prism, the deviation from the original direction in- 

 creasing gradually from red light successively through 

 orange, yellow, green, blue and indigo to violet, which 

 is the light that undergoes the greatest amount of 

 refraction. He concluded from his researches " That 

 the colours of all natural bodies have no other origin 

 than this ; that they are variously qualified to reflect 

 one sort of light in greater plenty than another " ; but 

 no sooner was this and like truths as to the nature of 

 colour announced than they were bitterly assailed by 

 philosophers who were unfamiliar with the experiments 

 upon which they were based, or held other views upon 

 light and colour. 



No wonder such opposition was disturbing to Newton, 

 and that it almost made him decide to do no work except 

 for his private satisfaction. " I was so persecuted with 

 discussions arising out of my theory of light," he wrote 

 in 1675, " that I blamed my own impudence for parting 

 with so substantial a blessing as my quiet to run after 

 a shadow " ; and a year later he remarked, " I see a 

 man must either resolve to put out nothing new, or to 

 become a slave to defend it." 



Everyone is now so familiar with electrical phenomena 

 that the explanation of lightning as an electric discharge 

 between two clouds, or a cloud and the earth, and of 

 thunder as the sound of the discharge, is readily intelli- 

 gible. Before the eighteenth century, when experi- 

 ments with various machines for producing electric 

 and other curious effects had excited great attention, 

 many strange conjectures had been made as to the 

 nature of lightning and thunder. Anaximander con- 

 sidered the phenomena as " caused by the wind enclosed 



