158 Mr. J. N. Lockyer. On Snn-Spot Observations. [Dec. 15, 



14. 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 

 Jnne, but mnch more abrupt, for only one of the old lines remained. 

 This is exactly analogous to the variations Tacchiui saw in the 

 spectra of the prominences in the region F to b, in December, 1872. 



15. In the first series of 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 series the total number of lines 

 seen was 104, and the iron lines faded away gradually, the last dis- 

 appearing on 26th July, 1881. 



16. So far as the observations have goue there has been no dif- 

 ference caused by the nearness of the spot to the limb. 



17. At the present time more than 75 per cent, of the most 

 widened lines are not represented in the spectra of terrestrial 

 elements. 



18. A line of titanium at wave-length 5865'0 and a line of barium 

 at wave-length 5852'5 are amongst the recent most widened lines. 

 Both these are long lines in the spectra of these metals. The line 

 at wave-length 5852*5 has been seen by Young in flames, with a 

 frequency of eight. 



No. Date. Greenwich No. 



10 January 20, 1880 306 



11 September 27, „ 367 



12 „ 29, „ 367 



13 „ 29, „ 368 



14 „ 29, „ 370 



15 „ 30, „ 367 



16 „ 30, „ 368 



17 „ 30, „ 370 



18 October 1, „ 367 



19 „ 1, „ 368 



20 „ 1, „ 370 



21 July 18, 1881 



22 „ 18, „ 521 



23 „ 21, „ 521 



24 „ 26, „ 525 



25 „ 26, „ 529 



26 „ 26, „ 522 



27 „ 28, „ 529 



28 „ 28, „ 525 



29 „ 28, „ 527 



30 „ 29, „ 529 



