308 



Corrections to the Reductions of Lieutenant Foster's Observations on 

 Atmospherical Refractions at Port Bowen ; with Addenda to the 

 Table of Magnetic Intensities at the same Place. By Lieutenant 

 Henry Foster, R.N. F.R.S. Read March 22, 1827. [Phil. 

 Trans. 1827,^. 122.] 



The error of which this paper contains a correction, consists in 

 the adoption of one exact second in arc, for the value of a division 

 of the long level of the repeating circle with which the observations 

 were made by the author for determining the amount of atmosphe- 

 ric refraction at Port Bowen, an account of which is published in 

 the Transactions of the Royal Society for 1826, Part IV. ; whereas 

 the true value is 10"'9 in arc. The error was discovered by Captain 

 Kater, who had occasion to use the instrument, and by him com- 

 municated to the author, who immediately took measures to ascer- 

 tain the fact ; and having, in Captain Kater's presence, convinced 

 himself of its reality, hastened to make the necessary recomputa- 

 tions of the Tables affected by it, and to submit them, so corrected, 

 to the Society ; explaining at the same time the error to have arisen 

 from erroneous information, given him at the time of receiving the 

 instrument, which being the same with that used by Captain Sa- 

 bine in his pendulum experiments, he took no steps to examine the 

 point ; as it never once occurred to him that there could be a doubt 

 on the subject. The Tables affected by this error are the 7th, 8th, 

 9th, 10th, llth, and 12th; and the corrections, which fortunately 

 in the three former Tables do not exceed 6", and in the three latter 

 do not amount to 2", are stated. 



The author observes, in a postscript, that the observations given 

 by Lieutenant Ross, at the end of the paper alluded to, must be now 

 wholly rejected, in consequence of the original observations involv- 

 ing the erroneous datum dependent on the level being left on board 

 the Fury at the time of her loss. 



He concludes by requesting the Society's acceptance of the ther- 

 mometer employed by Captain Parry and himself in the observations 

 in question, which was prepared with every possible care by Mr. 

 Daniell for the purpose. 



Corrections of an Error in a Paper published in the Philosophical 

 Transactions, entitled, " On the Parallax of the Fixed Stars." By 

 J. F. W. Herschel, Esq. F.R.S. Read February 22, 1827. [Phil 

 Trans. 1827, p. 126.] 



This notice is destined to rectify the consequences of an error in 

 a formula deduced in the paper alluded to, which was pointed out in 

 the errata to the Fourth Part of the Philosophical Transactions for 

 1826, by the re-computation of the table accompanying it, which 

 table so re-computed is annexed. 



