CONTENTS. 
VIII An Account of a fm'ill Telefcopical Comet feen at 
London on the lotb of June *717^ ^7. £dm. UaUey, LL. D, 
R. Soc, Seer. 
IX. An Account of Bocks i I.'Joannls Poleni in Gymnafio 
Paravino Phil Ord. Prof. & bcienr. Societatum Re^alium, 
qu3c Londini & Berolini font, Sodalis, De Mutu 
rnixto, Libri duo, 4‘®. Patavii 1717. J. Apollonii 
Pergjei Conicorum Libri O£to Sereni AntifTenfis At SeBhno 
Cjlindri Coni Libri duo. Fal. Reg, E Tbtatro Oxoti. 1710 . 
I. Jn Jdvertifement to Aftronomcrt, of the JJvajf 
tages that may accrue from the ObJerVation of the 
Moon’5 frequent Appulfes to the Hyades, during 
the Ihree next enfuing lears, 
O F all the Methods hitherto propofed for finding 
the Longitudes of Places for Geographical Ufes, 
none Teems more adapted to the purpofe, than that 
bv the Oeeultations of the fixe Stars by the Moon obferved in 
dillant Parcs: For thofe Immerfions of the Stars which 
happen on the dark Semicircle of the Moon, and their £« 
meriions from the fame, are perfe^ly momenianeous, with- 
out that Ambiguity, to which the Obfervacions of the Eclip- 
fes of the Moon and thofe of Jupiter s Satellites are fubje^. 
Befides, whilB the Moon is horned, and her weaker Light 
lefs daziing, an ordinary ftiort Teiefcope, fuch as bv Ex- 
perience is found to be manageable on Ship board, fuibces 
to obferve thofe vloments, even in the Occulta ions of ve- 
ry minute Stars: On which account, this way feems to bid 
fairelt for the defired Solution of the grand Problem of find- 
ing the Longitude at Sea. Bur fince it would be needlefs 
to enquire exa<5Hy what Longitude a Ship is in, when that 
of tlie Port to which fhe is bound is dill unknown it were 
to be wiflit that the P inces of the Earth would caule fuch 
Obiervations CO be made, in the ; ons and on the princu 
p4i Head-Lands of their Dominions, each for his own, as 
. might 
