142 Corrections in Right Ascension. [Feb. 



would think of undertaking it. I have dwelt upon this subject, 

 from an opinion (perhaps a foolish one) I entertain, that much of 

 the differences between Dr. Brinkley's and Mr. Pond's cata- 

 logues, may originate not in the observations themselves, but in 

 the manner in which those observations may be reduced. 



As to the superior accuracy with which our most important 

 observations would be reduced ; — corrections computed at the time 

 must alway be liable to error ; but if taken from tables, the accu- 

 racy of which is well established, this source of mischief must be 

 excluded. 



Lastly, as to the labour which the published corrections 

 would save ; — this, perhaps, it would be difficult precisely to 

 ascertain. In a former part of this paper, it has been said, that 

 three minutes would be required for obtaining the corrections of 

 a single star, in right ascension only; and I think those of north 

 polar distance cannot be procured in less than twelve; so that 

 fifteen minutes will be spent in getting both corrections. Now 

 it is not too much to say, that 20 zero stars may be observed 

 daily, in good observing weather ; and supposing 90 such days 

 to occur in the year, 450 hours will be consumed in obtaining 

 corrections, which were they published annually, might be 

 appropriated to some useful purpose. This, however, would be 

 the labour saved at one observatory only, say at Greenwich ; but 

 there are other observatories, where as well as at Greenwich, the 

 advantages would be felt ; some dependent upon Government ; 

 some belonging to public bodies ; and others, the property of 

 private individuals ; that we may form something like an esti- 

 mate, of the aggregate benefit, let us enumerate the principal 

 ones. Connected with Government, we have the observatories 

 at the Cape, at Kevv, at Portsmouth, and at Bagshot. Belong- 

 ing to public bodies, we have the observatories at Madras, at 

 Dublin, and at Oxford. As property of private individuals, the 

 observatories of Col. Beaufoy, and Sir Thomas Brisbane; of the 

 Rev. Mr. Catton, and Mr. Cooper ; of the Rev. Mr. Evans, and 

 Major Kater; of the Rev. Dr. Pearson and Mr. Sheepshanks. 

 He, therefore, who can doubt that an immensity of labour would 

 be saved by published corrections may be supposed able to 

 doubt almost his own existence. 



Now as to the expence of procuring the publication in ques- 

 tion. At present the apparent places* of 34 of the Greenwich 

 stars for eveiy 10th day of the year, are published by the Board of 

 Longitude ; so that the corrections for only 20,f remain to be pur- 

 chased. What the. Commissioners may pay for those of the 24, 1 

 know not; but I well know that daily corrections in right ascen- 

 sion and north polar distance of the 46 stars for one year may be 



* The corrections are preferable to the apparent places, as they enable the observer 

 to use the mean places from the latest determinations. 



■f The two stars of a Librae, and the two of a Capricorni, require only that the cor- 

 rections for one itar of each should be computed. 



