On a fluorescence spectrum of iodine vapour

In a number of most interesting papers Prof. R. W. Wood has shown that it is possible to obtain from iodine vapour at ordinary room temperatures, under the stimulation of light from the mercury are, a fluorescence spectrum, consisting of a number of lines ranging from λ = 7005·5 Å. U. to λ = 5337·63 Å. U. Further, he has shown that these lines can be divided into three series, one of which is stimulated by the light from the green line λ = 5460·74 Å. U. another by the light from the yellow line λ = 5769·60 Å. U.., and a third by the light from the yellow line λ = 5790·66 Å. U. Up to the present, he has identified in his photographs some 23 members in the series stimulated by the mercury green line, 10 members in that excited by the yellow line of shorter wave-length, and 13 members in the series arising from the excitation of the yellow line of greater wave-length. Moreover, by using apparatus of high resolving power, he has recently been able to show that in nearly every case the members of the green line series are complex and are in reality close doublets accompanied by a number of fainter companions.