OH. xxm.j SOME STATISTICS. 317 



15. At the commencement of October, 1881, there was a 

 change in the spectra of the spots similar to that which took 

 place in May and June, bat much more abrupt, for only one of 

 the old lines remained. This is exactly analogous to variations 

 observed by Tacchini in the spectra of the prominences in the 

 region F to I, in December, 1872. 



16. In the first hundred observations the total number 

 of most widened lines in the region F to b was fifty- seven, forty 

 of which were due to iron, whilst in the second hundred the 

 total number of lines seen was 104, and the iron lines faded 

 away gradually, the last disappearing on 26th July, 1881. By 

 November of that year more than 75 per cent, of the most 

 widened lines are not represented in the spectra of terrestrial 

 elements. 



The result of this inquiry with regard to chemical substances 

 which has been most carefully worked out, is indicated in the 

 accompanying table, giving the result of the work for two years 

 from 200 spots. 



STATISTICS OF THE MOST WIDENED LINES SEEN IN 200 SUN-SPOTS. 

 Total number of lines Total number 



