17] ON NEW TABLES OF THE MOON'S PARALLAX. 95 



plain that the results may be considerably affected by such an error in 

 the Parallax. It has often been remarked that differences of longitude 

 obtained by means of different occultations are not so consistent with each 

 other as might be expected from the precise character of the observation, 

 and I have no doubt that a great part of the discrepancy is to be at- 

 tributed to the use of an erroneous Parallax. 



Mr Maclear's observations at the Cape, combined with European obser- 

 vations, would doubtless furnish most valuable materials for a new deter- 

 mination of the constant of Parallax, care being of course taken to employ 

 correct Tables in the reductions ; and such a work would be a useful 

 contribution to Astronomy. 



In order to facilitate these and similar objects, Mr Stratford has calculated 

 the Parallaxes from my Tables for each Greenwich mean noon in the years 

 1840 1855, and has thus obtained the corrections to be applied to the 

 corresponding quantities given in the Nautical Almanac. 



These corrections are embodied in Tables which are appended to the 

 present paper. Subsequently to 1855, the Moon's Parallax given in the 

 Nautical Almanac is calculated from my Tables. 



