REPORT OF COMMITTEE ON OBSERVATORIES 141 



paring an answer. You wish me to express myself especially in 

 regard to Nos. (1), (2), and (4), and, although belated, I will do 

 this. 



The most important task that today confronts the southern ob- 

 servatories is, in my judgment, the production of really fundamental 

 determinations for a selected list of stars. Such determinations for 

 the southern hemisphere are still wholly wanting. We are hoping for 

 a series of such within the next few years from Gill, but it is of the 

 highest importance that we shall be in possession of several such 

 determinations, homogeneous and each as a check on the others, and 

 the establishment of a temporary observing station for this purpose 

 would therefore be a timely undertaking. 



The employment of a meridian circle, which should be used be- 

 fore and afterwards for similar determinations in the northern hemi- 

 sphere and which has proved itself to belong to the first rank of 

 first class instruments, would be wholly worthy of commendation. 

 By this means one would at least, to a great extent, remove one ele- 

 ment of uncertainty, the adopted flexure. It is possible that the 

 advantage from the employment of this device will not be so great 

 as you apparently hope, since the principal source of uncertainty 

 in our declinations arises from the uncertainty of the refractions, in 

 which local anomalies remain, arising partly in the observatory and 

 partly in its surroundings, and which can be rendered less and less 

 harmful in their effects through increase in the number of observ- 

 ing stations. 



The attempts which have hitherto been made to establish an ab- 

 solute system of declinations through comparison of observations 

 made in opposite hemispheres are founded on the supposition that 

 the refractions on both sides of the zenith are alike, and I doubt 

 whether this supposition is correct for the majority of those ob- 

 servatories upon whose observations we have had to rely up to the 

 present time for the establishment of systems of declination. The 

 correctness of this supposition seems to me especially doubtful in 

 relation to the two southern observatories which, up to the present 

 time, have afforded the most accurate places of the brighter stars. 

 The Cape, as well as Melbourne, observatories have the ocean to the 

 south and a heated continent to the north, and over these different 

 regions there may be very differently arranged masses of air. I 

 consider it, therefore, very important that the new observation sta- 

 tion should not have a similar position, but that it should be either 

 purely insular or purely continental. At the same time, the southern- 



