Table 181. 



DETERMINATIONS OF THE VELOCITY OF LIGHT, BY DIFFERENT 



OBSERVERS.* 



Table 182. 



PHOTOMETRIC STANDARDS. t 



• Quoted from Harkness, " Solar Parallax," p. 33. 



t This table, founded on Violle's experiments, is quoted from Paterson's translation of Palaz' " Industrial Pho- 

 tometry,"' p. 173. 



t The Violle unit is sometimes called the absolute standard of white lipht. It is the quantity of light emitted 

 normally by one square centimetre of the surface of melted platinum at the temperature of solidification. 

 Smithsonian Tables. 



176 



