The Spectrum of Neutral Iridium, Ir I

A new description of the arc spectrum of iridium has been made. The present data include 3100 wave-lengths of which 1937 have been accounted for as combinations between 214 energy levels. The normal electron configuration of the Ir I is $5d^{7}6s^2$ and the I.P. is approximately 9.2 volts. Tables of the most intense lines and of all of the energy levels are presented.