ASTRONOMY. 1G9 



"Time docs not permit me to go into more detail as to cacli of these 

 separate results, fall of interest tlionsli they are, and each of them rep- 

 resenting months of labor. 



"My object now is to generalize, to point out the conclusions that must 

 be drawn from this table and to see what are the broad lessons that 

 it teaches us. 



"A glance is suflicieut to show that neither apparent magnitude nor 

 apparent proper motion can afford a definitive criterion of the distance 

 of any fixed star— that different stars really differ greatly in absolute 

 brightness and in absolute motion. 



" The great cosmical problem that we have to solve is not so much what 

 is the parallax of this or that particular star, but we have to solve the 

 much broader questions — 



" 1. What are the average parallaxes of stars of the first, second, third, 

 and fourth magnitudes, compared with those of fainter magnitude? 



" 2. What connection does there subsist between the parallax of a star 

 and the amount and direction of its proper motion, or can it be i^roved 

 that there is no such relation or connection ? 



" With any approximate answer to these questions we should probably 

 be able to determine the law of absorption of starlight in space, and be 

 provided with the data at present wanting for determining with more 

 precision the constant of precession and the amount and direction of the 

 solar motion in space. And who can predict what hitherto unknown 

 cosmical laws might reveal themselves in the course of such an investi- 

 gation ? 



" It is important to consider whether such a scheme of research is one 

 that can be realized in the immediate future, or one that can only be 

 carried to completion by the accumulated labors of successive astron- 

 omers. 



"I have very carefully considered this question from a practical point 

 of view, and I have prepared a scheme, founded on the results of my 

 past experience. I have submitted that scheme for the opinion of the 

 most competent judges, and in their opinion, as well as my own, the 

 work can be done, with honest hard work, for one hemisphere, within 

 ten years. I have offered to do that work for the southern hemisphere 

 with my own hands, and a proposal for the necessarj^ instruments and 

 appliances is now under the consideration of my lords commissioners of 

 the admiralty. I need hardly add that in this matter I look confidently 

 for that complete consideration and that efficient support which I have 

 never failed to receive at their hands since I have had the honor to 

 serve them. 



" The like work will be undertaken for the northern hemisphere by my 

 friend, Dr. Elkin, who is now in charge of the heliometerat Yale Col- 

 lege, in America. It is at present the finest instrument of the kind in 

 the world. 



"I most earnestly trust that we may be granted health and strength 



