10 ANNIVERSARY ADDRESS. 
quoting the instructions which have been issued. I hope to have 
another opportunity of placing them before the members. Me 
You will have noticed that England counts the Observatories 
of Melbourne and Sydney in her list of stations; and I should 
like to detain you a few moments by saying what response Sydney 
is likely to make. Provision was liberally made by Parliament 
last year to enable the Colony to respond to this new call 
science, and the money has been placed at my disposal for this 
purpose. With this I shall be able to provide four high-class 
6-inch equatorials, similar to those which are to be used by 
the European observers, also two of 44 inches. We have 
remaining from the last transit of Venus one equatorial of 11} 
inches, one of 74, one of 5 inches, one of 4% inches, and one of 44 ' 
inches. With these I hope to be able to take up four stations, 
addition to the Observatory, and place two observers and two 
telescopes at each point. I cannot yet decide as to the use of 
photography, for it is of little or no use here without correspond 
ing observations on the other side of the world ; but I have ready, — 
if they are called for, one English photoheliograph and one of the 
American pattern. In Australia, along the east coast, we shall 
occupy the position which Sir George Airy thinks the best, Vim 
one where the sun is about 15 degrees above the horizon at the 
time that Venus makes egress. This gives the largest value of the : 
parallax factor consistent with such an altitude of the sun a8 : 
probably admit of accurate observation. If it were not for atmo — 
spheric interference, or difficulty in seeing distinctly, the best posi: i 
tion would be that from which the sun would be seen to be rising — : 
at the time Venus makes egress; and that point is in the centre . 
of Australia, The gain in parallax factor in such a positiom : 
however, does not compensate for the uncertainty caused by the 
atmospheric defects close to the horizon. In order to make the : 
best of our chances, I have selected elevated points on the er 
coast of New South Wales, where the observers, being : 
to 2,700 feet above the sea, may fairly expect to have @ cle 
view of the sun an hour after after sunrise, or when the egress” ye 
Place, than they would have if observing near the sea-level: 
