ome alterations in the mounting of the great
mirror. We found that sundry levers were loose which ought to be firm,
and we conjectured with great probability the cause of this, for
correction of which a change in other parts was necessary. The mirror
was then found to preserve its position much more fixedly than
before.... At night, upon trying the telescope, we found it very
faulty for stars near the zenith, where it had been free from fault
before. The screws which we had driven hard were then loosened, and
immediately it was made very good. Then we tried with some lower
objects, and it was good, almost equally good, there. For Saturn it
was very greatly superior to what it had been before. Still it is not
satisfactory to us, and at this time a strong chain is in preparation,
to support the mirror edgeways instead of the posts that there were at
first or the iron hoop which we had on it yesterday.

Nobody would have conceived that an edgewise gripe of such a mass of
metal could derange its form in this way.

Last night was the finest night we have had as regards clouds, though
perhaps not the best for definition of objects.

THE CASTLE, PARSONSTOWN,
_1848, Sept. 2_.

I cannot learn that the fault in the mirror had been noticed before,
but I fancy that the observations had been very much confined to the
Zenith and its neighbourhood.

1849

"In July the new constant-service water-pipes to the Observatory were
laid from Blackheath. Before this time the supply of water to the
Observatory had been made by a pipe leading up from the lower part of
the Park, and was not constant.--In May the new staircase from my
dwelling-house to the Octagon Room was commenced.--In the Report to
the Visitors there is a curious account of Mr Breen's (one of the
Assistants) personal equation, which was found to be different in
quantity for observations of the Moon and observations of the
Stars.--The most important set of observations (of planets) was a
series of measures of Saturn in four directions, at the time when his
ring had disappeared. They appear completely to negative the idea that
Saturn's form differs sensibly from an ellipsoid.--Among the General
Remarks of the Report the following appears: 'Another change (in
prospect) will depend on the use of galvanism; and as a probable
instance of the ap