76 



REPORT OF THE SECRETARY. 



The portion of the infra-re,l spectrum shown, which is that at present furthest 

 advanced, has been gone over several times, and each of the mor^e than 200 hnes 

 which occupy this p ate has been verified by many observations. The plate shows 

 but asmalpart of the region which is now being mapped, in all of which it is 

 leZJrT ''' '^^ ^'^"""^ encouraging. Although no investigation has 



been made of the mean.ng of the many significant lines in this great and now first 



exhibited region, it is reasonable to think that their study may lead to conclusions 

 ot only less importance than those resulting from the similar Frauenhofer lines in the 

 visible spectrum. It is especially believed that the science of meteorolo-y mav 

 become indebted to a study of this region for many indications of phenomena 

 which can not now be foretold with any degree of accuracy. 



