Address of the President of the Royal Society. 101 
limited to the occasion which has given rise to them. The considera- 
tions which apply to a telescope for the observation of the southern 
nebulz at Melbourne are no less applicable to one which might be estab- 
ished on a site from whence a great part of the southern nebule could 
also be observed (as well as those of our own hemisphere), but enjoying 
the immense advantage conferred by elevation into the higher and less 
dense strata of the atmosphere. Such sites are to be found in the Nil- 
Having learnt that a series of pendulum experiments at the gla 
avai 
have the opportunity of testing the exactness of the correction for 
buoyancy by vibrating his pendulum on both its knife-edges in the 
Vacuum apparatus which is now established at Kew. 
It is much to be desired that a similar series of pendulum experiments 
still greater extension, would seem 
to present a most favorable opportunity for the combination of pendulum 
i In such case the ulums of the Royal Society might 
be made available with excellent effect. i 
eas size of our printed volumes in the present year gives no 
unfavorable and, I ir i : 
of the Society, for I 
