Royal Astronomical Society., 519 



all the Greenwich planetary observations under the gratuitous super- 

 intendence and responsibility of the present Astronomer Royal, and 

 at his own suggestion. That work is now completed, and it is un- 

 derstood that the funds required for printing the results will be fur- 

 nished by the Board of Admiralty. The planetary places are com- 

 pared with the best existing tables, and the difference in heliocentric 

 longitude and latitude given exactly as in the recent volumes of the 

 Greenwich Observations, with a term which takes into account the 

 errors of the solar tables, should any sensible errors be therein found. 

 It need not be said to the members of this meeting that every care 

 has been taken, by duplicate computations and frequent comparisons, 

 to attain all practicable accuracy. The geometer who undertakes 

 the revision of the theory of a planet will now have no labour which 

 could be spared, and will be freed from every difficulty which is not 

 inherent in the problem itself; so that we may feel tolerable confi- 

 dence a few years will see us in possession of tables very far indeed 

 advanced towards perfection. 



But this work, laborious as it has been, yields in importance to 

 that which has been subsequently undertaken by the Astronomer 

 Royal (also gratuitously), the reduction of all the Greenwich ob- 

 servations of the moon, from Bradley downwards, together with a 

 comparison of the observed places with those deduced from Plana's 

 theory. Considerable progress has already been made. The R. A. 

 and N. P. D. of the moon's bright limb, with the corresponding 

 mean solar time, are computed; MS. tables, consisting of an ex- 

 tension of Damoiseau's tables for 1824, modified by the introduction 

 of Plana's coefficients and new terms, are nearly ready. The skele- 

 ton forms are prepared, and some steps in the computations taken. 

 The liberality of Her Majesty's Government has enabled the Astrono- 

 mer Royal to employ fourteen calculators on the work, which is con- 

 sequently advancing with all possible speed and ceconomy. Let us 

 hope that no pause will be made until a new set of lunar tables of 

 home manufacture are produced, which shall define the place of our 

 hitherto incorrigible satellite with the accuracy of the best observa- 

 tions, and sufficiently for the nicest purposes of geography. Your 

 Council feel that you will heartily join with them in their respect 

 for the talents, disinterested activity, and official piety of the Astro- 

 nomer Royal, and in thanks to the Government for its discriminating 

 and liberal patronage of our science. 



The Council are glad to have it in their power to report to the 

 meeting, that the difficulties which seemed to he in the way of suc- 

 cessful completion of the Cavendish experiment have been removed, 

 by new precautions against the radiation of heat from the large balls. 

 Though many experiments may, -in the early investigations, have 

 been apparently wasted, yet in reality much good must result from 

 the new light thus thrown upon the details of the operation itself, 

 and on the torsion-balance, which is the principal instrument em- 

 ployed. Considering the nature of the quantity required, the results 

 begin to assume a degree of accordance with each other which pro- 

 mises a very accurate determination of that great element of the 



