134 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 2 



poems " Corda Concordia." The stanza in which this is done is such 

 good science, as well as such good poetry, that I would like to quote 

 it: 



White orbs like angels pass 

 Before the triple glass, 

 That men may scan the record of each flame — 

 Of spectral line and line 

 The legendry divine — 

 Finding their mould the snme, and aye the same, 



The atoms that we knew before 

 Of which ourselves are made— dust, and no more. 



It is more than 200 years since Newton, passing his beam of light 

 in a darkened room through a prism, saw the rainbow-colored streak 

 of light upon the wall as the rays of different color were refracted 

 in different amount by the prism, and so was led to realize the 

 composite nature of white light. Unfortunately, Newton took his 

 light through a small round hole and he took it from the large round 

 sun; consequently, even if the sun had been all one color, the image 

 that he would have had thrown on the wall would have been like 

 the image that he got when it came through a pinhole in the window 

 shade. If only he had had the wit to set up a narrow slit so that 

 the image would have been sharp and not round, the master key 

 might have been discovered. 



Just after the first half of the nineteenth century was over, Kirch- 

 hoff and Bunsen made that simple but fundamental mechanical 

 change. Really this master key was found in a narrow slit — simply 

 in letting your light into this prismatic instrument through a slit so 

 narrow that you obtained a sharply defined image. As soon as that 

 was done, as soon as they took the light through a narrow slit into 

 their prism, with an eyepiece to look at it and a couple of other lenses 

 to make the light go in parallel rays through the prism — the new 

 doors were opened and the new worlds free to conquer. 



The next necessary advancement was the development of a more 

 delicate method of spectrum analysis. This came with Rowland, the 

 great Johns Hopkins physicist in the nineties. He developed an 

 engine for ruling diffraction gratings, the device that is used for 

 breaking light up into its components. The best of Rowland's 

 gratings are the joy, the envy, and the despair of the investigators 

 to-day — the joy of the man who has one, the envy of his colleagues, 

 and the despair of the man who tries to make one as good. Rowland 

 devoted years to the study of the solar spectrum and reported and 

 recorded in it the position of 20,000 lines, each one carrying its own 

 story of some substance in the sun. When Rowland was through 

 his work, 36 of the chemical elements had been identified in the sun. 

 Since that day, of course, a number more have been added because 



