530 PHILOSOPHICAL TRANSACTIONS. [ANNOI789. 



by the method of parallactic angles, and by the method of the nonagesimal, and 

 the results agreed together within a few loths of a second. By these 1 different 

 methods he also calculated the observations of Vienna, Berlin, and Viviers, in 

 order to show that the different latitudes of the moon, given by the various ob 

 servations, were not owing to any error in his calculations. For these places, in 

 which both the beginning and the end of the eclipse have been observed, he de- 

 duced the time of conjunction from the 2 phases conjointly, which have also 

 given the duration of the eclipse, which cannot be obtained from a single ob- 

 servation. 



The error of the tables which results from the observation at Greenwich is 

 4- 1& in longitude, and -f 1 \".b in latitude, at 20^ SS'" 47'.3 of apparent time, 

 taking for the longitude of the sun 2® 14° \& 54'^7> as deduced from the 

 Nautical Almanac, and that of the moon at the same time to be greater than 

 the sun by 26', as deduced from the same Almanac. He supposed also the 

 horary motion of the moon in the ecliptic, by taking it a half hour before and 

 after the conjunction, to be 36' 51" + 0^.6 for the hour following the con- 

 junction, and — 0".6 for the hour preceding the conjunction; the moon's horary 

 motion in latitude is 3' 24'''.3 ; the horizontal parallax of the moon minus that 

 of the sun at Greenwich, to be 60" 14'' .4 for the commencement of the eclipse, 

 and 6o' l6".4 for the end; the sun's diameter 31' 34".6, less by 3" than that 

 given in the Almanac, according to the correction which Dr. Maskelyne found 

 necessary to be made; the moon's diameter is stated as in the Almanac. In 

 the opinion of M. de la Lande, some correction ought to be made to the 

 parallax and to the diameter of the moon, as well as to the diameter of the sun ; 

 but on the one hand this would not make any alteration in the difference of the 

 meridians which Mr. P. has found; and on the other he thought proper to make 

 use of those elements the Nautical Almanac furnished, that being a work the 

 most perfect of the kind that ever appeared, and to which all astronomers and 

 navigators ought to pay the greatest attention. 



In fine, he compared the moon's longitude in conjunction deduced from the 

 eclipse with the new tables of the moon corrected by Mr. Mason, arid found the 

 longitude by those tables to be 2' 14° 17' 6".4, and the latitude to be 15' 1".3. 

 The error then of the new tables is -f 11 ".7 in longitude, and -j- 13".l in lati- 

 tude; but M. de la Lande having lately sent to him from Paris the place, of the 

 sun, calculated with the new solar tables (a most useful improvement which M. 

 de Lambre has, with much ingenuity, deduced from observations) he finds the 

 error in longitude to be -1- 27".4, the sun's place being 2^ 14° l6' 39".0 at 

 20^ 58"^ 47^3. 



The following table contains the observations of the eclipse, and the results 

 deduced from them. The first vertical column shows the name and place of the 



