THE WAVE THEOKY. 265 



attended with partial reflection. The dispersion of 

 light is no more incompatible with this than with any 

 other theory. Reflection and refraction are equally 

 explicable on both suppositions. Huyghens indeed 

 had proved this, and much more. Inflection may be 

 better explained by the wave theory than by its rival. 

 The colours of thin plates, which are perfectly unin- 

 telligible on the common hypothesis, admit of complete 

 explanation by the wave theory. In dealing with the 

 colours of thin films, of which the soap-bubble offers 

 a familiar example, Young first proved his mastery 

 over the undulatory theory. In the pursuit of this 

 great task he was able to apply to Newton's Theory 

 of Fits the Theory of Waves, and to determine the 

 lengths of the undulations corresponding to the dif- 

 ferent colours of the spectrum. 



We now approach a phase of Young's career which 

 more specially concerns us. The Royal Institution, 

 as already stated, was founded by Count Rumford, sup- 

 ported by many of the foremost men in England. The 

 King was its patron, the Earl of Winchilsea its first 

 president, while Lord Morton, Lord Egremon^, and Sir 

 Joseph Banks were its vice-presidents. On January 13, 

 1800, the Royal Seal was attached to the charter of the 

 Royal Institution. Dr. Thomas Garnett was appointed 

 Professor of Natural Philosophy and Chemistry. During 

 his previous residence in Bavaria, Rumford had ruled 

 with beneficent but despotic sway, and the habit of 

 mind thus engendered may have made itself felt in 

 his behaviour to Dr. Garnett. At all events, they did 

 not get on well together. On February 16, 1801, Davy 

 was appointed Assistant Lecturer in Chemistry, Direc- 

 tor of the Chemical Laboratory, and Assistant Editor 

 of the Journals of the Institution. The post of Pro- 



