, [32.2 J 
An auount of the Eclipfes or ingrefles ^/Jupi- 
ters Satellits into his jhadow and fuch Emer- 
fions of them from it as will be vifible at the Ob- 
fervatory at Greenwich in the three lajl 
Months of this year i6^7,.fentina Letter to the 
Publiflier/ro;;z 7. F. Aftroa Reg. 
SIR, 
I Here fend you an account of the E-cliffes or Ingre^es of Jufi- 
ters Satellits into his rtiadow, and fuch emerfions of them from 
it as will be vifible at the Obfervatory in thcthree lad moneths 
of this year ; they are calculated from new Tables 1 made thislaft 
fummer, and I hope fo exadly that the Ingrejfes of the firft will 
feldom be found when obferved, to differ above 5 minutes from 
the time ftated, the 3 but little more 5 the Eclipfes of the fourth 
andfecond I dare not promife you (hall agree fowelh for I find 
their mmons evidently intangled with inequalitys, which it will 
require a long time and many more accurate ohfervations to deter- 
mine and limit, then i have yet obtained : thefe Eclipfes have been 
cfteemed, and certainly arc a much better expedient for the dif- 
covery of the Longitude then any yet known, by reafon that they 
happen frequently, and arc eafily obferveable with a Telejcope of 
1 2. foot^or for need with one of 8. Thefe Ingrefes (^nd emerfans alfo 
if vifible) from the time till the opofition of the O and ^ happen 
truely on the right hand or m antecedence of the planet, but if they 
(hall be obferved with 7V/^/io/?^/ of only two Convex gUjfes which 
invert the object, they appear on the contrary or left fide of him. 
If thefe find acceptance with our ingenious friends the Eclipfes of 
the next year (hall be imparted early enough to be publilhed in the 
*Decemhr Tranfai^ms, I am 
SIR, 
yours, df?e» 
7. FLAMSTEB V>. 
Obfcrvatory Sept. 22. i683. 
