ADVISORY COMMITTEE ON ASTRONOMY II9 



observatory and the observatory at Washington have taken part in 

 the extension of this work southward. Lately, at Albany, obser- 

 vations of stars down to the eighth magnitude have been extended 

 to the thirty-seventh parallel of south declination, the results of 

 which are now in preparation to form a catalogue of 10,000 stars. 



Included in the program 01 the great astrophotographic survey 

 under the leadership of the National Observatory at Paris (to which 

 allusion has already been made in the foregoing), is a plan to deter- 

 mine through measurement of photographic plates the positions of all 

 stars brighter than the eleventh magnitude. This gigantic under- 

 taking is proceeding with a success as to the northern hemisphere 

 which scarcely could have been anticipated by men practically 

 acquainted with the difl&culty of such tasks. The state of the work 

 in the southern hemisphere is far less flourishing, though the situa- 

 tion is not without an element of hope. The burden of this great 

 enterprise has fallen very largely upon the English and French gov- 

 ernments. The United States has taken no part in it. 



It may become desirable in the future that the Carnegie Institu- 

 tion should undertake a section of the southern sk}^ should some 

 one, or more, of the participants in the southern hemisphere fail — 

 a contingency not without the bounds of possibility. 



In the foregoing paragraphs I have indicated in a very summary 

 way what has been accomplished in observations of precision upon 

 the relative positions of stars. This work has exercised the energies 

 of considerably more than one-half the working force of astronomers 

 during the nineteenth century. The observatories already estab- 

 lished for, and now engaged in, this work may be depended upon to 

 keep up a fair balance of output in relation to other branches of 

 astronomy, so far as the ordinary types of such work is concerned, 

 and in relation to the northern hemisphere. In all countries except 

 the United States, governments may be relied upon to render fairly 

 adequate support to this class of observations, since the relations of 

 this work to the practical uses of mankind, notably in geography 

 and navigation, appeal more directly to the motives of official 

 administration. 



Fundamental determinations of star-positions, however, belong to 

 a class of highly specialized researches, giving free play to originality 

 of conception and invention of methods. Oiily a very few of those 

 which have been made in the entire history of modern astronomy 

 are entitled to the claim of high rank. To sustain the proper bal- 

 ance toward diSerential, or secondary, observations, there should 



