254 SCIENCE PROGRESS. 



shown in the spectroscope. The lines are contorted in both 

 directions, and sometimes to a very considerable extent, 

 indicating wind movements on the sun, reaching and some- 

 times exceeding ioo miles a second. 



We had here a means of determining whether the 

 orange line was produced by the same gases which gave the 

 red and blue lines, because if so, when we got any altera- 

 tion in the position of the red and blue lines, which always 

 worked together, we should get an equivalent alteration in 

 the position of the orange one. 



I found that the orange line behaved quite differently 

 from either the red or the blue lines ; so then we knew that 

 we were not dealing with hydrogen ; hence we had to do 

 with an element which we could not get in our laboratories, 

 and therefore I took upon myself the responsibility of coin- 

 ing the word helium, in the first instance for laboratory 

 use. 



This kind of work went on for a considerable time, and 

 what one found was, that very often in solar disturbances 

 we certainly were dealing with some of the lines of sub- 

 stances with which we are familiar on this earth ; but at the 

 same time it was very remarkable that when the records 

 came to be examined, as they ultimately were with infinite 

 care and skill, it was found that not only did we get this 

 line in the orange indicating an unknown element associated 

 with substances very well known, like magnesium, but that 

 there were many other unknown lines as well. Within a 

 few months of my first observations, several new lines about 

 which nothing was known were thus observed. 



THE DISCOVERY OF OTHER UNKNOWN LINES, 1869. 



The place of the orange line D 3 I determined on 

 20th October, 1868. Among many other lines behaving 

 like it, two at wave-lengths 4923 and 5017 were discovered 

 in June, 1869, and afterwards another at 6677, while Pro- 

 fessor Young noted another in September, 1869, at 4471. 

 He wrote : — 



" I desire to call special attention to 2581*5 [ = 4471 on 



