( 10 ? ) 
III. A Catalogue of Eclipfes of the four Satel- 
lites of Jupiter, for the Year 1731. By James 
Hodgfon, F. d^. 5. and Mafter of the Boyal 
Mathematical School at Chrift’s Hofpital, 
London. 
I HAVE been long importuned by feveral of my 
Friends to publifh a Catalogue of Eclipfes of Ju- 
piter's Satellite Si to the Intent that fuch Perfons as 
are furniihed with proper Inftruments, and want nei- 
ther Leifure nor Inclination to obferve them, may nc» 
longer negleQ: the frequent Opportunities tint offer, 
for want of timely Notice. 
The great Number of Eclipfes that happen in a 
Year, as appears by the following Catalogue, amount- 
ing to 3 52 ; notwithftanding the fourth Satellite will 
pafs wide of the Shadow, after the middle of Janu- 
ary next ; the Eafe with which they are obferved, 
elpecially fince the great Improvement made to the re- 
fie&ing Telefcope by Mr. Hadley j the little Skill 
that is required to make the Obfervations, fince the 
Difference of Times, when obferved by the larged 
Glades, and the fmalled through which they may be 
feen, amounts to fcarce one quarter of a Minute ; 
render thefe Obfervations the mod proper of any that 
the Heavens afford us, at prefent, for determining the 
Longitude of Places ; and I may venture to alferr, 
that there are very few Places of Note upon the Surface 
of our habitable Globe, whofe Longitudes are already 
known, that have not either been abfolutely deter- 
P mined 
