210 
PROCEEDINGS OE SECTION A. 
The Observations . — At 5 hours 10 minutes the equatorial was 
pointed to the sun. The several small clusters of spots which had 
been observed on the solar surface for some few days previous were 
clearly visible as the sun gradually cleared the neighbourhood of the 
horizon. There was no difficulty whatever in distinguishing the planet, 
for Mercury at once appeared in the field as a most perfect sphere, 
intensely black, with remarkably clear and sharply-defined periphery. 
Tor some time I sat iutently watching this interesting object as it 
slowly moved across the great solar surface. Particular attention was 
given to an examination of the effect of different magnifying powers 
and of various intensities of light by a manipulation of the combination 
of dark glasses used in the eyepiece of the telescope, but this produced 
no change whatever in the appearance of the planet. The definition 
was perfect, and there was not the slightest trace of haze, band of 
light, or vaporous aureola around the disc of Mercury. Attention was 
next bestowed upon a very miuute white spot that appeared upon the 
surface of the planet. I was aware that a similar object had been 
noticed by several observers during previous transits, although 1 had 
failed to see anything of the kind at the transit or 1881, which I 
observed with a small telescope under distressing conditions. In this 
instance the steady unchangeable appearance of the object left no 
doubt in my min.d whatever that it was something more tangible than 
an optical illusion. I removed the lower magnifying power, and 
applied one of 450 diameters, and at first thought I saw two white 
spots close together; but after the eye had accommodated itself to the 
change the second spot assumed a very uncertain appearance, and for 
this reason I doubt its existence altogether; the first, however, 
remained unchanged. When about to observe internal contact I was 
somewhat startled by what appeared for the moment to be a slight 
indication of ligament, but the phenomenon was only momentary, and 
I regard it as purely optical. When external contact occurred the 
limb of the sun and that of the planet were remarkably clear, sharp, 
and well defined. There was not the slightest trace of disturbance in 
the limbs of the two bodies, and I have every confidence in recording 
the phase as a pure geometrical contact. Contact geom&trique sans 
deformation. I very carefully watched for the planet when it separated 
from the sun, but no trace of its periphery could be distinguished 
from the dark space beyond. 
Taking the mean of the three chronometer records, the following 
are the corrected times of the observations, viz : — 
h. m. sec. 
Internal contact ... ... 7 23 42 45 
Geometrical external contact ... 7 25 28*00 
The above are the mean times at Brisbane observatory, in latitude 
27° 28' *00" S., and longitude 10 hr. 12 min. 06*4 sec. E. We occupied a 
position of about G,534 feet south and 10,428 west of the Brisbane 
observatory. 
Begardiug Mr. Stanley’s observatory it will probably be found in 
general practice that a telescope is capable of doing better work when 
placed within a building with the roof entirely off than in one enclosed 
by the common revolving circular dome. In the former the air 
currents are more likely to he nearly uniform in temperature, while in 
the latter type opposing currents of air of unequal temperature are 
