L Cumus Oh/erVations of the Tranpt of the !Body and 
Shade of JupkcTS Fourth Satellite o^er the Dif^ue 
of the Tlanet. Communicated by the ^yerend 
'Mr. James Pound, R, S, S. 
fnding by the Tables of Jupiter’s Satellites that the 
Fourth Satellite was to pafs over the Difque of 
Jupiter the 1 5 //^ of this prefent February, at Night; we 
were very defirous to obferve the fame with the 
Hugeman Telefcope, having never before, fince I have 
had the Ufe of it, been able, by reafon of the foul- 
nefs and inconftancy of the Weather, tamake any to- 
lerable Obfervation of this kind, 
Ac thro’ a fliorc Tube, we faw all the 4 Sa- 
tellites, the 3 outermoft on the Eafi fide of Jupiter, 
and the innermoft near the Weflern Limb approaching 
to an Eclipfe. The Fourth at that time was about 
half a Semidiameter of Jupiter from the Edfiern Limb.- 
Then it proved Cloudy till about 8\ at which time 
01110’ the long Glafs) we could fee only the fecond 
and. third Satellites, the hrft being behind Jupiter in 
the Shadow, and the fourth entred upon the Difque. 
We faw at this time a dark Spot, a little Morthward 
of the great Northern Zone, and near the Eajlertr 
Limb, where the Satellite was to enter on the Difque ; 
which Spot we took for the Shade of the Satellite. 
The Clouds then again intercepted our View, till 
8^ 53'. JEe^.T. at which time the firfl Satellite was 
lately emerged out of the Shadow, and the Spot ad- 
vanced fo far, that we perceived it would arrive at ‘ 
the middle of Jupiter, near two Hours fooner than 
the 
