REPORT OF COMMITTEE ON OBSERVATORIES I07 



minations of stellar parallax. * * * Therefore, detemiinations 

 of these has been considered an important feature for the work of 

 the proposed observatory'. 



(3) * * * " It is considered highly desirable that another very- 

 large reflector should be provided for this use [determination of 

 radial motion] in the southern hemisphere. Were such an instru- 

 ment provided it could also be employed in other spectroscopic 

 researches requiring powerful optical means and also in the photog- 

 raphy of nebulae. * * * 



(4) "The extension from — 32° to the south pole of zone obser- 

 vations upon the general plan adopted by the Astroiwmische Gesell- 

 schaft. The Cordoba Obser\'atory has secured the necessary obser- 

 vations for the zone — 22° to — 32°. Only one fourth of the sky 

 remains to be covered. * * * 



(5) "It is thought desirable that extensive observations for vari- 

 ations of latitude should be made in the southern hemisphere some- 

 what upon the plan now adopted for the northern hemisphere in the 

 international sendee. * * * 



(6) " During recent years, and especially at the lyick Observator>', 

 very thorough sun-eys of the stars in the northern sky have been 

 carried out for discover^'^ and measurement of close double stars. It 

 is considered desirable that similar investigations should be carried 

 out with at least one large telescope for that part of the southern sky 

 which is be}'ond the reach of northern obser\'atories. * * * 



(7) " Eventualh' certain astrophysical researches of precision, re- 

 quiring great optical power, will be required in the southern hemi- 

 sphere to complete the evidence relative to certain classes of objects 

 which have been, or are about to be, investigated in the northern 

 hemisphere. ^ t^ ^ 



' ' In view of these considerations, it would be of great service if the 

 consensus of experienced astronomical opinion could be obtained in 

 regard to the relative urgency of obser^^ations which ought to be 

 undertaken now in the southern hemisphere and which are inade- 

 quately provided for at existing institutions there, whether such 

 observations have been alluded to in this statement or not. * * ^k 



' ' It would also be useful to learn whether anj- similar plans are 

 known to be under consideration by others ; or whether there is any 

 prospect of such. * * >i= 



' ' lyCtters have been addressed to astrophysicists in relation to the 

 proposed astrophj'sical obser\'ator>' for which a site in southern 

 California is contemplated. The object of this observatory would 

 be to investigate the physics of the sun, and, especially, the amount 

 and variation of solar radiation, with apparatus more powerful than, 

 and in conditions of atmosphere superior to, any which have been 

 hitherto available for the purpose. Your suggestions and advice 

 upon this head would also be very acceptable." * * * 



