INDEX 



tricky, 205 ; his observation of 

 chemical combinations confirms 

 Datum's atomic theory, 256, 259; 

 his improvement of lenses, 325, 

 326, 327. , 



Wortrnan, J. L., his fossil lineage of 

 the edentates, 121. 



Wundt, Wilhelm Max, his psycholog- 

 ical discoveries, 414, 415. 



" X RAY," its discovery, 1, 2, 228. 



YOUNG, CHARLES AUGUSTUS, his spec- 

 troscopic researches, 70. 



Young, Thomas, his establishment of 

 the undulatory theory of light, 27, 

 192-204, 225; confirms the identity 

 of galvanism and electricity, 205; 

 practising medicine and studying 

 Egyptian hieroglyphics, 206 ; the 

 real discoverer of the ether 231, 

 232. 



Z6LLNER, JOHANN KARL FRIEDRICH, 



his cometary theory, 54, 55; his in- 

 terpretation of the diversities in the 

 spectra of stars, 73. 



