The lower part of the house serves merely for a habitation; but above is a large octagonal room, which, being now seldom wanted for astronomical purposes, is used as a repository for such instruments as are too large to be generally employed in the apartments first described, or for old instruments, which modern improvements have superseded. Among the former is a most excellent ten-feet achromatic, by the present Mr. Dolland, and a six-feet reflector, by Short, with a clock to be used with them. In the latter class, besides many curious and original articles, which are deposited in boxes and cupboards, is the first transit instrument that was, probably, ever made, having the telescope near one end of the axis; and two long telescopes with square wooden tubes, of very ancient date. Here, likewise, is the library, which is stored with scarce and curious old astronomical works, including Dr. Halley's original observations, and Captain Cook's Journals. Good busts of Flamstead and Newton, on pedestals, ornament this apartment; and in one corner is a dark narrow staircase, leading to the leads above, whence the prospect is uncommonly grand; and to render the pleasure more complete, there is, in the western turret, a _camera obscura_, of unrivalled excellence, by which all the surrounding objects, both movable and immovable, are beautifully represented in their own natural colours, on a concave table of plaster of Paris, about three feet in diameter. On the north side of the Observatory are two small buildings, covered with hemispherical sliding domes, in each of which is an equatorial sector, made by Sisson, and a clock, by Arnold, with a three-barred pendulum, which are seldom used but for observing comets. The celebrated _Dry-well_, which was made to observe the earth's annual parallax, and for seeing the stars in the day-time, is situated near the south-east corner of the garden, behind the Observatory, but has been arched over, the great improvements in telescopes having long rendered it unnecesary. It contains a stone staircase, winding from the top to the bottom. The Rev. John Flamstead, Dr. Halley, Dr. Bradley, Dr. Bliss, Dr. Nev. Maskelyne, and John Pond, Esq. have been the successive astronomers-royal since the foundation of this edifice. * * * * * TWIN SISTERS. (_For the Mirror_.)