94 CARNEGIE INSTITUTION 



Appendix A to Report of Committee on Astronomy. 



GENERAL PLAN FOR FURTHERING SPECIAL 

 RESEARCHES IN ASTRONOMY. 



Ill the general report which your Committee has already submitted 

 to the Trustees of the Carnegie Institution it has endeavored to 

 point out some of the more immediate needs of astronomy, and 

 especially such as it has supposed could possibly be provided for 

 with the present means of the Institution. 



Your Committee has also considered the possibility of many 

 undertakings for which, on account of the great expense involved, 

 the Carnegie Institution might not be prepared to make provision 

 on a broad foundation at tlie present time. However, we do not 

 feel justified on this account, in a report which aims to set forth the 

 progress and needs of astronomical research, in omitting mention of 

 these schemes, which may be regarded as parts of a single homoge- 

 neous plan. Furthermore, as we shall endeavor to show more 

 fully below, it is quite possible for the Carnegie Institution to make 

 a modest beginning through the appropriation of comparatively 

 small sums from existing funds. 



The need for special undertakings in astronomy, such as are con- 

 templated by us, arises in part from the desire to secure special 

 conditions of atmosphere. If the atmosphere were everywhere in 

 a perfect state of calm, with no differences of temperature except 

 those due to increasing altitude, the telescopic images of celestial 

 objects seen through it would be perfectly steady and distinct. 

 Under the actual conditions of observations as we experience them, 

 the telescopic image is in a state of rapid and inces.sant vibration. 

 On rare occasions there may be improvement over the ordinary 

 conditions, but even at best the full optical possibilities of tele- 

 scopes are never realized. Fortunately, it happens that at certain 

 points on the earth's surface the meteorological conditions are such 

 as greatl}^ to decrease these difficulties of seeing. Experience has 

 shown that excellent definition is the rule rather than the exception 

 at certain tropical or semi-tropical stations of small elevation above 

 the sea. Indeed, a lofty mountain peak is often inferior from this 

 point of view, though for some purposes it ma}' offer very great, if 

 not indispensable, advantages in that class of ob.servations where 

 transparency to light and heat is quite as essential as good defini- 



