Royal Astronomical Society. 1 35 



it is made by one who unites both characters in so remarkable a 

 degree. 



The corresponding series of lunar observations is now so far ad- 

 vanced, that only a small revision of some of the later years is want- 

 ing. Ten years' reductions in Right Ascensions and North Polar 

 Distance are printed, the Government having supplied the necessary 

 funds ; and the formation of the equations for the correction of the 

 elements is in progress. It is remarkable that, though all the lunar 

 tables now existing to which observation has contributed, or which 

 have not been formed from theory alone, have been founded on data 

 procured from Greenwich, that Observatory is yet able to show 

 that its records are not exhausted. Singularly connected as it has 

 always been with the progress of lunar astronomy, its history has 

 never presented so remarkable an epoch as the present time. The 

 reduction, in the most systematic and usable form, of its old meri- 

 dian observations, is the work of the Astronomer Royal, who sug- 

 gested and undertakes the extra-meridional course of observation 

 mentioned in the last report. 



The altitude and azimuth instrument intended for this purpose 

 has now left the engineer's hands, and is in those of Mr. Simms, for 

 the completion of the micrometers, levels, graduations, &c. It is in 

 a very forward state. The peculiar tables which the reduction of 

 the observations will require are in preparation, and no long time 

 will elapse before it is in use. 



The connexion of Pulkowa, Altona, and Valentia with the Obser- 

 vatory of Greenwich has the calculations now completed. The re- 

 sult for Pulkowa is not yet printed ; that for Altona differs very little 

 from the one which was found many years ago. The result for Va- 

 lentia has been compared with that derived from Colonel Colby's 

 survey, the elements for the figure of the earth being those which 

 were given some years ago by the Astronomer Royal, in the Ency- 

 clopedia Mctropolitana. It appears that the geodetic longitudes of 

 Liverpool and Kingston arc a very little too large, that of Valentia 

 a very little too small ; being just what would take place if the or- 

 dinary assumptions employed in determining the figure of the earth 

 were disturbed by an unknown source of attraction beneath the sur- 

 face of Ireland. A memoir on these results is now in preparation 

 by the Astronomer Royal. 



The ordinary star-observations at Greenwich have been, during 

 the past year, in a great measure devoted to filling up the blanks 

 in one element (whether Right Ascension or North Polar Distance) 

 which exist in the recently published catalogue of 1439 stars. 



By information received from Colonel Estcourt, who is employed 

 upon the survey of the North American boundary, it appears that 

 the latitudes of various points have been obtained by the use of ex- 

 cellent twelve and fifteen-inch altitude and azimuth instruments. 

 The differences of longitude have been found (the country present- 

 ing no more such difficulties as those described in last year's Report) 

 by instantaneous signals of gunpowder flashes compared with transit 

 observations, made at intervals of three minutes. The accuracy of 



