11 
experiments made with an invariable pendulum . 
always covered except at the moment of noon, I had reason 
to believe that none of the adjustments were ever disturbed. 
In observing the times of transit, a steady going chronometer 
made by Henry Frodsham was used, and was found parti- 
cularly convenient from its beating half seconds. A compa- 
rison between the clock and chronometer, was always taken 
before and after the passage of either sun or star. The time 
of transits shown by the face of the clock, was then deduced 
by direct proportion. All the comparisons are given in a 
separate table. 
It occasionally happened, owing to the state of the wea- 
ther, that one of the stars was partially obscured at the time 
of its passing the meridian, so as to limit the observation to 
one or two wires only, whilst the transit of the other, over 
the whole five was obtained ; in such cases the mean of the 
rates for the clock has been deduced, by giving a value to 
each, in the ratio of the number of wires observed. 
In the observation of the coincidences, the same mode was 
followed as in the experiments at Greenwich. The tempe- 
rature of the pendulum, however, was more frequently taken 
by means of a small telescope, placed outside of the room, at 
a window to the south, and on the same level with the ther- 
mometer, suspended a little below the middle of the pen- 
dulum for that purpose. 
The weather on the whole was favourable during this 
series ; it became somewhat unsettled toward the close ; but 
as no day passed without at least one transit for the rate of 
the clock, I had no reason to be dissatisfied with any of the 
observations taken. 
A second series was made in July, under more favourable 
