SCIENTIFIC SUMMARY 
ASTRONOMY. 
Oecultation of a Star by Jupiter . — On September 14, 1879, a very in- 
teresting phenomenon was observed at the Melbourne Observatory, the 
oecultation of the 6|-magnitude star, 64 A'quarii by the planet Jupiter. 
The phenomenon was observed by Mr. Ellery, with a magnifying power of 
600 on the 8-inch equatorial telescope, under very favourable circum- 
stances, the sky being clear and the definition steady and good. Mr. Ellery 
describes his observations as follows (M. N. of Roy. Astr. Soc., Yol. XL., 
page 140) : — ‘The smallness and faint light of the star as compared with the 
satellites first attracted attention. The star first appeared to touch the 
planet’s limb at 10 h 5 m 19 s Melbourne mean time, and was visible in that 
position for nearly two minutes, when, while still making a projection on the 
planet’s outline, it all at once appeared as if seen through a mist or haze, and 
entirely projected on the planet's limb. This faded away in about ten seconds, 
leaving still a decided nipple-like projection on the edge of the planet, as if 
the planet itself bulged out, without any signs of the true light of the star ; 
and at 10 h 7 m 43 s- 8 this disappeared leaving a clear outline to the disc.’ 
The oecultation was also watched by Mr. White, the first assistant, with a 
power of 200 on a 4^-inch equatorial reflector. The phenomenon seen 
agreed with that noted by Mr. Ellery, but the times were 10 h 6 m 23 s- 7 and 
10 h 7 m 40 s, 4 respectively, the two first differing very materially from that of 
Mr. Ellery’s, but it is very doubtful if they refer to the same phenomenon. 
Mr. Turner observed the oecultation with a power of 350 on the great 
Melbourne Reflector of four feet aperture. He states : ‘ At the moment of 
contact, the star did not instantly disappear, but seemed to possess a visible 
disc, the limb of Jupiter seeming to advance gradually upon it, the star bv- 
and-by appearing to be bisected and then gradually disappearing altogether. 
The time of final disappearance was 10 h 7 m 47 s ‘6 Melbourne mean time. 
The time of first contact was about 35 s before final disappearance, — certainly 
not less; it might be more. For about 10 s after disappearance the star 
could be seen through Jupiter's atmosphere as a speck of light seen through 
groimd glass.’ 
These observations are of great interest, though it is probable that the 
