h Street.

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Just published, price 1s.

THE STEREOSCOPE,

Considered in relation to the Philosophy of Binocular Vision. An Essay, by
C. MANSFIELD INGLEBY, M.A., of Trinity College, Cambridge.

London: WALTON & MABERLEY, Upper Gower Street, and Ivy Lane, Paternoster
Row. Cambridge: J. DEIGHTON.

Also, by the same Author, price 1s.,

REMARKS on some of Sir William Hamilton's Notes on the Works of Dr. Thomas
Reid.

"Nothing in my opinion can be more cogent than your refutation of M.
Jobert."--_Sir W. Hamilton._

London: JOHN W. PARKER. West Strand. Cambridge: E. JOHNSON. Birmingham: H.
C. LANGBRIDGE.

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LEEDS LIBRARY.

LIBRARIAN.--Wanted a Gentleman of Literary Attainments, competent to
undertake the duties of Librarian in the Leeds Library. The Institution
consists of about 500 Proprietary Members, and an Assistant Librarian is
employed. The hours of attendance required will be from 10 A.M. to 8 P.M.
daily, with an interval of two hours. Salary 120l. a year. Applications,
with Certificates of Qualifications, must be sent by letter, post paid, not
later than 1st December next, to ABRAHAM HORSFALL, ESQ., Hon. Sec., 9. Park
Row, Leeds.

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XYLO-IODIDE OF SILVER, exclusively used at all the Photographic
Establishments.--The superiority of this preparation is now universally
acknowledged. Testimonials from the best Photographers and principal
scientific men of the day, warrant the assertion, that hitherto no
preparation has been discovered which produces uniformly such perfect
pictures, combined with the greatest rapidity of action. In all cases where
a quantity is required, the two solutions may be had at Wholesale price in
separate Bottles, in which state it may be kept for years, and Exported to
any Climate. Full instructions for use.

CAUTION.--Each Bottle is Stamped with a Red Label bearing my name, RICHARD
W. THOMAS, Chemist, 10. Pall Mall, to counterfeit which is felony.

CYANOGEN SOAP: for removing all kinds of Photographic Stains. Beware
purchasing spurious and worthless imitations of this valuable detergent.
The Genuine is made only by the Inventor, and is secured with a Red Label
bearing this Signature and Address, RICHARD W. THOMAS, CHEMIST, 10. PALL
MALL, Manufacturer of Pure Photographic Chemicals; and may be procured of
all respectable Chemists, in Pots at 1s.,