MATHEMATICAL PAPER S. 5 
APPENDIX. 
H E afcertaining of the difference of longitude between 
various places on the globe, particularly between im- - 
portant headlands and feaports, and alfo between places where 
aftronomic obfervations are made, to perfect the knowledge 
of the heavens, and to. improve ere and geography, are: 
very defirable obj ects. Obfervations of eclipfes of the moon 
and of Jupiter’ s fatellites have frequently been made ufe of for 
this purpofe. When the beginning or ending ] has been obferv- 
ed in two places, the difference in time is the difference of 
meridians, which- may be reduced to degrees, at the rate of 
15° per hour. . But. the earth's fhadow is fo imperfectly. de- 
fined at the moon, that the beginning, or ending of a lunar 
eclipf fatisfactori ined, that rm difference 
: Jepended upon.. The beginning or ending sfs "o 
her s fatellites can be determined with more precion but 
ture e the telefcopes, which are made ufe of for the obferva- 
tion : nor is me diljegenge s uem viu two Emi 
Pei Nu oer R mmerfions and e 
fions, to be compared with Er une ones, Of late years, 
, obfervations of dolar eclipfes, of occultations of fix- 
Nye the moon, and- of tranfits of the inferior planets 
over the fun’s difk, when made under favourable circumftances, 
have been moft fought for, and ufed, when they could be ob- 
tained, for determining differences of meridians, In thefe ob- 
T: the difference of times is not the difference of me- 
B ridians, 
