is Mr. liEKSCYLEi/sand Mr. South's observations of the apparent 
flag. The weight of this effectually secures the stability of 
the foundation stone. The southern pier likewise consists of 
a large stone, two feet in thickness, resting on a bed of brick- 
work, carried downwards ten feet below the surface. So 
effectual are these precautions, that stars pass with perfect 
regularity along the whole extent of the declination wire, 
while the heaviest waggons are traversing the street within 
forty feet of the instrument, which, in one instance, has kept 
its adjustments, and been actually employed as a transit for 
six weeks, without sensible alteration. Indeed, whilst in 
Captain Huddart's possession, it was almost exclusively used 
as a meridian instrument. 
The object glass of the seven feet equatorial is the work 
of Mr. Tulley, and may perhaps be regarded at present as 
the chef d’oeuvre of that eminent artist. It is five inches in 
clear aperture, and in distinctness under high magnifying 
powers* is probably excelled by no refractor existing. Proof 
of this will be found in the separation and measurement of 
the most minute double stars, such as <r and n Coronas Bore- 
alis, in its sharp definition of the double ring of Saturn, 
and various other of the most delicate celestial objects. It is 
mounted on a polar axis of brass, furnished with declination 
and hour circles of the same metal, the work of the late 
Mr. Sisson ; being, in fact, those of the old equatorial sector 
of the Royal Observatory, committed to our care for this 
purpose by the Council of the Royal Society ( to whom our 
thanks are therefore due) and of which a more particular de- 
* Under favourable circumstances, with a power of 600, the discs of the two 
stars of v Coronas and of <7 Coronae ; of £ Bootis and of £ Orionis, are shown per- 
fectly round, and as sharply defined as possible. 
