Royal Astronomical Society. 313 
resting his claim to our gratitude wholly and solely upon its con- 
duct and its result. Itis only thus that you can fairly affirm the 
verdict which the Council has already given, and the approval of 
which it so confidently expects at your hands ; for you must re- 
member, gentlemen, that no services whatever, except those ex- 
pressed in the resolution awarding this medal, can count in the 
smallest degree as a justification of that resolution. I am the more 
desirous of impressing this upon you, when I consider that this is 
the first occasion on which a medal has been awarded for the manner 
of employing money intrusted by the public to our charge: so that 
in fact, this defence, if I may so call it, of the award, is more than 
the explanation of the Council to their constituents, or at least must 
become something more. When it has gained your approbation, it 
must ge forth to the public, and to the Government, as the account 
which the Society renders of the funds which were placed in its 
hands, as the proof that those funds were worthily administered. I 
am not, of course, ailuding to the mere vouchers of pecuniary in- 
tegrity, to the proof that money asserted to have been spent upon 
apparatus was actually so expended, but to the justification of a 
yet higher character. 
The actual observations, meaning those which are printed in the 
Memoir, are 2153 in number, varying from ten to thirty minutes 
each ; ‘so that I am under the mark considerably when I say that 
600 hours were spent at the apparatus, in the mere act of watching 
the oscillations of the torsion rod. To this must be added nearly as 
many more in the series of experiments, of which the results were 
afterwards abandoned on account of the anomalies of the pendulum. 
Add to this the time expended in contrivance, in computation, and 
in deliberation, and it will appear that it is not often that any 
single inquiry has called forth so determined an exercise of in- 
dustry and perseverance. The experiments were commenced in 
October 1838, and were continued until May 1842. With the 
exception of about a couple of months of interruption, caused by 
the severe accident which, as all present are aware, happened to 
Mr. Baily in the summer of 1841, there was a continued succession 
of trials. This long and patient investigation gives a peculiar value 
to the result : the effects of the several conditions of the atmosphere 
cannot but have been eliminated, since the printed experiments, or 
those which were made after the anomalies of the pendulum were 
got rid of, run over nearly a whole year. 
I cannot but call your attention to the spirit in which every part 
of the investigation was conducted. When all possible precau- 
tions had been taken to secure the stability of the pendulum; when 
it had been ascertained that no degree of concussion, whether in 
the room which contained the apparatus, or in that immediately 
above, would produce any sensible effect upon it ; when every pains 
had been taken to remove thermal, electric, or magnetic disturbance; 
and at the moment when it seemed next to certain that the result, 
whether that of Cavendish or another, was about to come out clearly, 
