129 
the length of the pendulum at Madras. 
one plane. The frame, its two parts being firmly screwed 
together, was then placed, levelled by means of a spirit level, 
and fixed to the blocks in the firmest manner: the frame en- 
closing the agates was next put up, levelled, and screwed in 
its place, the Y’s elevated, and the pendulum hung ; the 
knife edges were then lowered upon the agates; when I had 
the satisfaction to find, from the precautions which I had 
taken, that the pendulum was most correctly in its place. In 
this distant part of the globe, there is an anxiety in handling 
and fixing any new apparatus which is not felt in England, 
where the maker of it is ready to give assistance, as well as 
to repair any damage that may chance to have been done: 
here, little or no assistance can be obtained ; and if the use 
of any part of the apparatus should be mistaken, and the part 
forced into a wrong place, the injury may be fatal to the ex- 
periments, as it cannot be repaired here ; it therefore affords 
no small gratification when an instrument is firmly secured, 
uninjured, in its proper position. 
The pendulum is precisely the same, in all its parts, as that 
used by Captain Kater at the different stations of the Trigo- 
nometrical Survey of England, and which he has fully de- 
scribed in the Philosophical Transactions for 1819. Any far- 
ther description therefore of its construction, will here be 
unnecessary. 
The next operation was to fix the arc for measuring the 
vibrations. The clock-case was of handsome mahogany 
enriched with projecting mouldings, with the door in front 
of plate glass. The mouldings kept the pendulum at too 
great a distance from the part of the case where the arc could 
otherwise have been fastened, and it became necessary to 
MDCCCXXII. S 
