( 4*7 ) 
not many, or great Errors, could be in my Obferva* 
tions. 
The greateft Part of the EcIipTes, that were the mod 
accurately made, may eafily be diftinguifhed by the 
two, or more Numbers of the Time of Obfervation : 
The hrft of which fhews the Moment of the Begin- 
ning of the Eclipfe • the following, the Times when 
farther advanced : As in anEmerfion, the firft Number 
{hews the Time, when the Satellite appears like a 
fmall obfcure Spot:, the following Numbers, when 
brighter, or quite emerged out of Jupiter ' s Shadow } 
and fo contrariwife in an fmmerfion. 
But altho* this might have fufhced, yet for greater' 
Certainty and Satisfaction, I have noted which Obfer- 
vations were good, which doubtful, or bad : Even the 
latter of which may be of Ufe in fome Cafes, where 
better are wanting. 
The calculated Times of the Eclipfes I have infert- 
ed, where I had them from others, or could calculate 
them my felf, as being of good Ufe to amend the Ta- 
bles of Mr. Flamfteed , Caffini , or others, taken Notice 
of in the Column on Purpofe. And for the fame Rea- 
fon 1 thought good to add the Place of Jupiter alfo. 
And laftiy, 1 thought it good to mention the Length 
and Power of the Telefcope I ufed ; as being, in fome 
Meafure, neceffary in the comparing Obfervations of 
different Places ^ becaufe Obfervations may differ feve- 
ral Seconds, by the different Length and Goodnefs of 
the Telefcope ufed j a long and good Telefcope {hew- 
ing the Satellite, when the Shadow of Jupiter doth 
but juft touch it : Whereas a fhort, or bad one, doth 
not (hew it, until one half, or more, of the Satellite is 
enlightened. Which Difference is moft remarkable in 
the 
