Appendix V. 



REPORT ON THE ASTRO-PHYSICAL OBSERVATORY. 



As iudicated in my last report, tlie general work of the Observatory for the fiscal 

 year has continued to be the investigation of the infra-red solar spectrum described 

 in the general body of the report for 1893. This work may conveniently be divided 

 into three parts : 



A. General spectrobolographic work, 



B. Special spectrobolographic work. 



C. Instrumental work^ including manufacture of new apparatus and the perfec- 

 tion of old. 



A. The general spectrobolographic work of the year may be summed up as follows : 

 (A "holograph" is an automatic reproduction of the curve representing the distribu- 

 tion of the energy in the infra-red spectrum.) 



A complete record of these holographic curves, automatically registered by the 

 apparatus upon glass plates, has been filed for future investigation, the work in its 

 present stage being confined, as has already been stated, to the exploration of this 

 hitherto unexplored region and the identification of its landmarks. 



The result of the Avork has been extremely satisfactory, so far as regards the niimber 

 and importance of the lines found. The accompanying illustration (see plate) show- 

 ing a portion of the infra-red spectrum from the region l.ijii to 2.2/ii, beyond what a 

 few years ago was considered the limit of the infra-red spectrum, will show the 

 detail and clearness with which the present apparatus is capable of rendering what 

 can, only in the absence of a better word, be called the "appearance" of this region, 

 since, it must be borne m mind, no human being has senses capable of directly 

 discriminating between these interruptions, or of directly perceiving the form of 

 this display of energy. 



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