50 PICKERING— INTERNATIONAL SOUTHERN TELESCOPE. 



[April 18 



fore, be $400,000 or $500,000, which at most would only be a third 

 of that required for an observatory of the first class and of the usual 

 form. 



Method of Administration. 



The administration and management of the fund would, of 

 course, rest with the donor. If it were left to mc, I should at once 

 write to the principal makers of glass for estimates of the cost and 

 time required to furnish a disk of glass seven feet in diameter and 

 one foot thick. An expedition to South Africa would next be 

 planned, equipped with , the two-foot reflector of the Harvard Ob- 

 servatory. This instrument would be mounted in the best available 

 location, and regular work undertaken which would test the stead- 

 iness and other qualities of the atmosphere. Test? wouUi .ik-..^ be 

 made of various adjacent localities, with refractvi.'.r telescopes of 

 four, five, or six inches aperture. Meanwhile, correspoi. ^-^nrr v/rmirl 

 he opened with all those astronomers likely to give useful au. 

 and a committee would be formed of such astronomers as would 

 attend a meeting at an early date. Thus, no time would be lost. 

 The form of mounting would be the principal subject to be discussed 

 at the first meeting, and the work of construction would be begun as 

 soon as this point was settled. The results of the first expedition 

 would probably serve to determine whether a better location could 

 be found in South Africa than that we now occupy in Peru. 



Discussion of Results. 



Not only from its size, but from its exceptional location, this tele- 

 scope ought to give better results than those previously obtained in 

 almost every department of astronomical science. Its principal use 

 will be in photography, determining the positions, brightness, and 

 spectra of faint stars, especially novae and variables, in depicting 

 clusters and nebulae, in studying the distribution of faint stars, in 

 discovering and following faint satellites and asteroids, in meas- 

 uring parallaxes and proper motions, and, in general, in studying 

 all the properties of stars beyond the reach of smaller instruments. 



In visual work, very high powers could be employed, without the 

 difiiculties usually encountered from diffraction when a very small 

 emergent pencil is used. Owing, also, to the great light gathering 



