TRANSIT OF MERCURY. 171 
appearance of the sun, with various sized stops on object-glass, I 
determined to use the whole aperture, definition being very good. 
Having the advantage of an electric chronograph, so that the 
beats of the Sydney Observatory standard sidereal clock were 
recorded on a tape side by side with the ticks of my chronometer 
only a short time before and after the phenomenon, errors in 
recorded times were practically eliminated. 
In the early morning the weather was particularly fine ; but, 
about the time of ingress, thin clouds commenced to spre read over 
the sky, which, however, did not cause any difficulty in the 
observation of the ingress, definition being then very good; at 
i lanet see me m ike 
shadow entering on the sun’s as like the umbra in an 
indentation I saw at ingress was occasioned in this way, or by 
planet. I waited until certain that it was really Mercury before 
“06nd the electric key, and the record thus made and reduced to 
mean time, is November 8th, a.m., 8° 22™ 5-005. 
Chik pichic mentally, after oe event, the distance between the 
cusps at the time recorded, I estimated this at 6 to 7-tenths of the 
in 
telescope was slightly touched accidentally, causing vibrations 
which had sca scarcely ceased when the limbs of the planet and sun 
appeared to be tangential. This was recorded at 8h. 23m 
39°75s. a.m. Sydney mean time. As I felt in some doubt 
ual] ATR until it became evident that Mercury was 
wholly projected on the sun’s 
I watched the planet at intervals during its transit, the definition 
most of the time being magnificent. The sun spots an d markings 
were very distinct, although thin fleecy clouds were spread over 
the whole of the sky, I failed to notice any peculiar appearances, 
oe perhaps a very faint suspicion of a halo or yellowish light 
unding the intensely black disc of the planet, and on a 
brighter than the general illumination of the sun’s s disc. 
to an optical illusion rather than a real “Jornal 
- arene ag 
