Appendix V. 

 ASTRO-PHYSICAL OBSERVATORY. 



At present the astro-pbysical observatory is under the immediate direction of 

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

 work in detail lias hiiu largely iu 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 jileased 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 " Holograph " is an auiomatic reproduction of the energy curve, made by the 

 new process.) 



1892. 



July 



August 



September. . 



October 



Kovember . . 

 December . . 



1893. 



January 



February ... 



March 



April 



May 



June 



Days 



available 



for bolo- 



metric 



work. 



Number 

 of bolo- 

 grapba 

 taken. 



Character of holographs. 



Remarks. 



Time mostly occupied by work 

 on wave-length apparatus. 



Taken with glass prism Observatory closed fifteen 



days. 

 Do. 

 Observatory closed ten days. 



-do 



23 Glass prism . 

 22 : do 



Grating 



24 Glass and rock s.alt . 



14 j do 



40 do 



27 Kock-salt prism 



Time nrrnpied witli grating 

 work. 

 Do. 



SUMMARY : 



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



Total number of holographs taken : 



(1^ With glass prism 114 



(2) With rock-salt prism 54 



(3) With grating 8 



Total 176 



60 



