450 



OPTICAL PROJECTION 



WER 



291 ; combustion-lantern, 308 ; 



simple electroscope, 398 

 Wernicke's direct prism, 293 

 Wheatstone's kaleidophone, 252, 



266 



White light, composition of, 285 

 Wire rings for soap-films, 326 

 Wood's lime-jet, 65 

 Woodward, Col., and concave 



amplifiers, 187 



ZIR 

 Work, an exhibitor's, 113 



YELLOW, compounded, 303 



ZEISS'S eye-pieces, 188 ; lenses, 194 



objective-changers, 189 

 Zirconia for O.-H. light, 68 



