REPORT OF COMMITTEE ON OBSERVATORIES 1 25 



about to publish zones — 40° to — 42°, the rest following in course 

 of a few years) with the plate constants which will also be pub- 

 lished any computer can construct a catalogue of all stars to the 

 seventh, eighth, ninth, tenth, or eleventh magnitude, as he may see 

 fit. 



A, 5. The discovery and measurement of close double stars is an 

 important branch of astrometry which is far behind in the southern 

 hemisphere. I have great hopes that ere long a powerful telescope 

 will be erected at Johannesburg for this purpose. Mr. Innes, re- 

 cently my secretary, has been appointed in charge of the obser\^a- 

 tory there. At present his work is officially that of meteorologist, 

 but I have great hopes that, having regard to his proficiency as a 

 double-star observer, his enthusiasm and his power of exciting scien- 

 tific sympathy, and the number of wealthy and large minded resi- 

 dents there, he will ere long be provided with a first class equatorial 

 fitted for research on double stars. Meanwhile I propose to lend 

 him the portable observatory^ I used at Ascension and a 6-inch equa- 

 torial of m}' own, which he is to employ in making an independent 

 determination of the magnitudes of a number of stars on each of 

 the C. P. D. plates. 



But this prospect should in no way interfere with the erection of 

 a second large telescope devoted to the same work, for independent 

 comparison is at least as important in this department as in funda- 

 mental meridian work. 



I had the satisfaction, when I visited Johannesburg last May, of 

 selecting a site, outside of the town, which I have little hesitation 

 in saying is one of the finest in the world for an observatory. It 

 is nearly 6,000 feet above sea level, the atmospheric conditions seem 

 to be most favorable, and on my recommendation the site, 10 acres 

 in extent, has been secured by the government. 



So much for astrometry. I agree with you that the provision 

 made under the direction of Pickering at Arequipa and the labors 

 of Roberts and Innes in South Africa sufficiently fulfill the require- 

 ments of photometric research as compared with that class of work 

 in the northern hemisphere, and the work of the Carte du Ciel ap- 

 pears to be provided for. 



Astrophysics. 



B, I. 1 have no hesitation in saying that what is required is the 

 erection of the largest possible reflecting telescope for exact re- 

 searches on the spectra and motion in the line of sight of the fainter 



