SIR NORMAN LOCKYER 361 



considered ideally useless at the time they were made, have been the 

 origin of the most tremendous applications. One instance suffices. 

 Faraday's trifling with wires and magnets has already landed us in 

 one of the greatest revolutions which civilization has witnessed ; and 

 where the triumphs of elettrical science will stop no man can say. 



This is a case in which the useless has been rapidly sublimed into 

 utility so far as our material wants are concerned. 



I propose to bring to your notice another "useless" observation 

 suggesting a line of inquiry which I believe sooner or later is 

 destined profoundly to influence human thought along many lines. 



Fraunhofer at the beginning of this century examined sunlight and 

 starlight through a prism. He found that the light received from the 

 sun differed from that of the stars. So useless did his work appear 

 that we had to wait for half a century till any considerable advance 

 was made. It was found at last that the strange "lines" seen and 

 named by Fraunhofer were precious indications of the chemical sub- 

 stances present in worlds immeasurably remote. We had, after half 

 a century's neglect, the foundation of solar and stellar chemistry, an 

 advance in knowledge equaling any other in its importance. 



In dealing with my subject I shall first refer to the work which has 

 been done in more recent years with regard to this chemical condition- 

 ing of the atmospheres of stars, and afterwards very briefly show how 

 this work carries us into still other new and wider fields of thought. 



The first important matter which lies on the surface of such a gen- 

 eral inquiry as this is that if we deal with the chemical elements as 

 judged by the lines in their spectra we know for certain of the exist- 

 ence of oxygen, of nitrogen, of argon, representing one class of gases, 

 in no celestial body whatever ; whereas, representing other gases, we 

 have a tremendous demonstration of the existence of all the known 

 lines of hydrogen and helium. 



We see, then, that the celestial sorting out of gases is quite differ- 

 ent from the terrestrial one. 



Taking the substances classed by the chemist as non-metals, we 

 find carbon and silicium — I prefer, on account of its stellar behavior, 

 to call it silicium, though it is old fashioned — present in celestial 

 phenomena. We have evidence of this in the fact that we have a 

 considerable development of carbon in some stars and an indication 

 of silicium in others. But these are the only non-metals observed. 



