300 Astronumicul Sociefi/. 



is the same in botli hemispheres, we have an opportunity of 

 ascertaining the united effects of refraction, instead of the dif- 

 ference between the refraction of a star near the pole and of a 

 circumpolar star remote therefrom. 



In regard to the distance between the north and south poles, 

 by combining Dr. Brinkley's observations with those of Sir 

 Thomas Brisbane, the result is, that the mean of 141 south 

 polar distances deduced from l-tl of his observations, and ap- 

 plied to Dr. Brinkley's north polar distances =179° 59' 58",92 

 or l",08 in defect. Dr. Brinkley's refractions were applied to 

 the southern observations, using the interior thermometer. 

 The same mean, obtained by using Mr. Bessel's north polar 

 distances and computing by Mr, Bessel's refractions [Astron. 

 Fundam.), using the exterior thermometer, is 180° 0' 1",72 or 

 l",72 in excess. 



1 °. Among the observations are some by reflection. These 

 afford us the means of determining the zenith point, and 

 thence the distance between the zenith and polar points, or 

 the co-latitude. 



Co-latitude by Cano;ws 56° 11' 8",63 



Siriits 9,16 



Fomalhaiit 9 ,95 



Mean = 56 11 9 ,25 



Latitude = 33 48 50 ,75 

 2°. The results of observations on bo!h the solstices of 1822 

 appear to show the latitude of Paramatta = 33° 48' 42''. — 

 (No. 37, Der Ast. Nachrichten.) 



The observations of the Dec. solstice of 1821 give the mean 

 zenith distance of the solstitial point, Jan. 1 , 1 822, = 1 0° 2 1' 2",23 

 —(No. 20, Der Ast. Nach.) 



The mean obliquity of the ecliptic,"^ 

 taking the mean obliq. of Jan. 1, 1816, I = 2s 9" 47 or 

 = 23° 27' 49",21 and secular diminution [ J - / */ ,uo 



= 43" J 



Latitude 33 48 49,29 

 If we use Mr. Bessel's obliquity =22° 27' 45",66 the lati- 

 tude will be =33° 48' 47",89. 



The result of all tile observations sliows that Dr. Brinkley's 

 constant of refraction (57",72) is as exact as can be desired, 

 when the refractions are computed by the interned tliermome- 

 ter; also that, when computed by the c.r/nv/f// thermometer, 

 Mr. Bessel's refractions recjuire no correction worth notice. 



A connnimicatioa was also read from Colonel Beaufoy, in- 

 closing a series of observations of Jupiter's satellites, at Bushey 

 Heath, near Stanmore, between April 1816 and December 

 '324; and another series of observations of solar and lunar 



eclipses, 



