154 
REV. F. FALLOWS’S observations with an invariable 
of his inquiries, which are readily obtained, and easily performed and ac- 
complished. 
The Lords Commissioners of the Admiralty haying furnished this observa- 
tory with the invariable pendulum (No. 4. Jones), which had for several years 
been most strictly examined by Captain Sabine at Mr. Browne’s, in Portland 
Place, London, and subsequently by the same learned gentleman in the course 
of his inquiries in different parts of the earth, I wished at the earliest opportunity 
to have a series of experiments made upon it, which might unite every possible 
degree of accuracy on the part of the observers, as well as the utmost stability 
in the structure intended for supporting the pendulum. From many unforeseen 
circumstances, I found at length that the completion of this observatory would 
be delayed for a considerable time, though previously I had, too fondly per- 
haps, anticipated finishing it at a much earlier period ; and I therefore took 
advantage of a small out-liouse (then of no further use) within a short distance 
of the building, to erect a stout brick pier, well bonded, for the support of the 
small transit instrument ; the same which I used in forming my catalogue of 
273 southern stars reduced to the beginning of 1824. 
Temporary chases were made for meridian observations ; and the recess for 
the clock (Molyneux’s *) and pendulum was soon constructed in a most sub- 
stantial manner within a few feet of the transit. The top of this recess con- 
sisted of a thick strong Robben-Island stone, perforated in the middle, and 
chiselled out at the upper part, for the reception of the brass plate containing 
the agate planes upon which the knife-edges of the pendulum rest. This plate 
was securely fastened to the stone with cement ; and I found that when the 
agates were once truly adjusted to level, they remained (with one exception 
only, and I think this might be attributed to some error in one of the small 
levels,) during the whole of the observations that succeeded. It is hardly 
worthy of remark that at the end of each day’s work the knife-edges were 
screwed up from the agates, and remained so till the commencement of another 
series on the first favourable opportunity. The clock (adjusted to sidereal time 
and corrected for rate by the stars,) was placed in the recess, having the bottom 
of the case resting upon a large block of stone embedded in well-wrought clay, 
and the back of the case was tightly screwed to a strong piece of well seasoned 
* The new clock, not the old one. 
