From Newton to Kirchoff. 



207 



well merited by the patient industry with which he pur- 

 sued his investigations. 



These dark lines of spectrum are the alphabet in which 

 the chemistry of the sun is written. Too delicate for the 

 unaided eye to behold and reposing among the rich colors 

 of the light, this elegant system remained after its dis- 

 covery, more than half a century, without a key to its trans- 

 lation. 



While the illustrious men already named were treading 

 the path of discovery in optics, others whose names will 

 soon appear were making curious and important researches 

 in chemistry. A kind of chemical analysis was being de- 

 veloped from observations made on the nature of colored 

 flames. The solar spectrum and colored flame, like dis- 

 tant mountain springs which feed two independent streams, 

 were the beginnings of two series of discoveries which 

 were found to converge as they lengthened until optics and 

 chemistry mingled to produce the grander science of celes- 

 tial physics. 



It was before the discovery of the dark lines of the spec- 

 trum, even as far back as the year 1750, that Thomas 

 Melville noticed that peculiar colors could be imparted to 

 flame by adding certain substances to the combustible 

 material. The attention of Sir John Herschel was long 

 afterward drawn to this subject,, for in 1822 we find him 

 saying " the colors thus communicated by different bases 

 to flame afford in many cases a ready and neat way of 

 detecting minute quantities of them." Twelve years later, 

 Mr. Fox Talbot called especial attention to the magnificent 

 crimson color of the flame of burning strontium, and at the 

 same time, in terms more emphatic than had been used by 

 Herschel, declared his conviction that the smallest portion 

 of this substance could be detected by the color of the light 

 of its flame with even more certainty than by any other 

 means. 



