C ^99 ] 
An ExtraSi of a Letter from Mr. ]. Flamfleed Aftr. 
Reg. and Reg. Soc. S. gi^vrng his calculation of the 
Eclipfes of Jupiter s Satellites for the Year 1687. 
' gather mth a Table of the Parallaxes of the Orb^ and 
anEphemerisofJupiters Geocentric Place for the 
fame Year \ to which is added an Obfervation of the 
Eclipfe of the Moon^ No^emb. '^o^ 1685. 
Lisbon ^ and Mr. Flamfted's own Obfer'vation of 
the Eclipfe of Jupiter by the Moon on March 3 if/?. 
Give you here a Catalogue oF all the Eclipfes of t^s Sa* 
Jl tellites, for the enfueing year 1687. togather with it 
3 Tables, one of his Geocentrick places, the other of the Pa- 
rallaxes of his Orbit tD every day in the faid Year. This is 
the Ath. Catalogue I have got publifhed in tJie Tranfaftions. 
With the ij?,, printed D^'^'. 16^1. Num. 154. I fliewed their 
ufts, and how -by their help the difference of Longitude, 
betwixt any two places on the Earth, where they fhould be 
Gblerved, might be determined. And I Taught a Method 
of finding out within what fpace on our Globe any of them 
would be obfervable-: This was done in Englifli for the ufe 
of our Country-men. Next Year in December 1684. I re- 
peated thofe Direftions in Latin Num.\i6%. pag. 760, for the 
benefit .of Forreigners. In the two Trahiactions of Decern. 
%^.Num. 177 and ijS, with the, Catalogue of Eclipfes I 
deferibed a faiall Inftruraent, and fihewed by the help of it, 
the faid Catalogue, aiad the Tables of % Geocentrick places' 
and Parallexes, the appearances of the Satellits at dny tinle- 
within the compafi of that Yean might be ^ifcovered and de- 
lineated ; if therefore the; Reader defire to be infbrmedcon- 
cerning the ufe of the Catalogue and Tables herewith print- 
ed 
