Appendix V. 



ASTR< (PHYSICAL OBSERVATORY. 



Ai present the astro-physical observatory is under the immediate direction of 

 the Secretary, but owing to the pressure of other occupations the conduct of the 

 work in detail has lain largely in the hands of Mr. F. L. O. Wadsworth, who 

 received the appointment of senior assistant on October 10, and to whose efficient aid 

 the Secretary is pleased to acknowledge his obligation. 



The general work of the observatory for the year has pertained to the investiga- 

 tion of the infra-red portion of the spectrum, briefly referred to last year, and 

 described in general in the body of my report. It may conveniently be classified 

 under three general heads : 



A. General spectro-bolographic work. 



B. Special spectro-bolographic work. 



C. Instrumental work, including manufacture of new apparatus and the 

 perfection of old. 



A. The general holographic work of the year, (which can be carried on only when 

 the sky is unobscured by clouds or haze), is summed up as follows: 



A " Bolograph" is an automatic reproduction of the energy curve, made by the 

 . new process. 



SUMMARY: 



Total number of days available (i. c, of sunshine days) for bolometric work 83 



Total number of holographs taken: 



(I i With glass prism 114 



(2) Willi rock-salt prism .. 54 



(3) With grating 8 



Total 176 



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