226 REPORTS FROM THE SECTIONS. 
Note on the Transit of Mercury, on May 6th, 1878. 
By Joun Tessvtt, F.R.A.S. 
[Read before the Astronomical Section, 13 June, 1878.] 
A transit of Mercury across the sun’s disc occurred on the 6th of 
May last, astronomical time.—The ingress took place before the sun 
rose, so that the early part of the transit wasnot seen here. Owing to 
clouds having partially removed, I obtained the first view of the 
Le about 19h. 58m. with my 38jinch refractor. At t 
thought I could perceive a faint whitish spot on pe 
senses disc, ‘but I could see nothing of the kind shortly after- 
wards with the 41-inch equatorial. The eae bevient provided 
with Cooke’s prismatic reflecting eye-piece and a magnifying power 
of 180 diameters, was employed in the ber viititin of the egress. 
was free from spots, and there was no ri 
anything like a satellite. At 20h. 48m. 19-3s. observatory mean 
solar time, when I estimated the thread of light between the limbs of 
the sun and planet to be about a sec econd of are in breadth, the 
planet suddenly threw out a narrow ligament and immediately 
became somewhat pear-shaped, as ‘represented in figure 1. 
“get at this time reminded me very much of that chal 
by in at Greenwich with ri 3}-inch alt-azimuth during 
the egress of the planet in November, 1868, and represented in his 
diagram on page 12 of the 29th volume of the Ro oyal Astronomical 
Society’s Monthly Notices. The ligament observed by me was 
nearly as black as the planet itself, ‘and rendered it very difficult 
to estimate the time of the geometrical or apparent internal con- 
tact of limbs. This phase occurred about twenty-two seconds 
after the formation of the ligament, or at 20h. 48m. 41°3s. 
It appears from the Sydney Morning Herald of May 8th that 
the times of the internal contact as iutcoal at the Sydney 
vations were respectively, 114, 74, and mi inches. Their times 
correspond to 20h. 48m. 13:05s. 20h. 48m. 22-00s. and 20h. 
48m. 33-63s. at my observatory. Taking into consideration 
the fact that the differential effect due to parallax is in this 
