8o LIGHT SCIENCE FOR LEISURE HOURS. 



been made, and there really seems to be no reason for 

 believing that we have as yet nearly reached the limits 

 of the knowledge which spectroscopic analysis is capable 

 of supplying. Indeed, the invention of a new form of 

 spectroscope the ingenious automatic spectroscope of 

 Mr. Browning promises soon to be rewarded by a 

 series of discoveries as important as any which have 

 hitherto been made. We propose briefly to indicate 

 the present position of our knowledge respecting the 

 great central luminary of our system. 



The spectroscopic observation of the eclipse of 

 August 1868 had shown that the strange prominences 

 seen during total eclipses of the sun are vast masses 

 of luminous vapour, hydrogen flames, we may call 

 them, considering how largely hydrogen enters into 

 their constitution. Only we must remember that it is 

 hydrogen glowing from intensity of heat simply, and 

 not burning hydrogen, that constitutes these promi- 

 nences. Now it had long been recognised that the 

 coloured prominences spring from an envelope of a 

 similar nature surrounding the whole surface of the 

 sun. Father Secchi, of the Collegio Romano, in a lecture 

 given to the pupils of the Ecole Ste. Genevieve, had 

 thus in 1867 described this envelope (whose existence 

 he was the first to recognise): f The observation 

 of eclipses furnishes indisputable evidence that the sun 

 is really surrounded by a layer of red matter, of which 

 we commonly see no more than the most elevated 

 points.' One of the first and most interesting results 

 of the eclipse observations was Mr. Lockyer's con- 



