A FINE 'CAPTAIN KATER' PATTERN SIGHTING COMPASS BY THOMAS JONES, LONDON, CIRCA 1815
the 5in. mica card with arsenic green scale, signed in manuscript Thomas Jones No. 62 Charing Cross, steel needle, removable inclined lens assembly (later) and folding sight with lens -- 5¼in. (13.3cm.) wide

This pattern was invented by Captain Kater in 1811. A small inclined mirror and lens eyepiece assembly allows simultaneous viewing of the scale and the distant object via the opposite vertical folding sight. Kater's design pre-dates Schmalcalder's use of a prism but was not patented and became superseded by it.
Literature: Scientific Instrument Society, Bulletin No. 127 (December 2015) p.36.

Condition Report
good overall condition - note the lens assembly is a modern replica.

We are pleased to provide you with a general report of the condition of this property. Since we are not professional conservators or restorers, we urge you to consult with a restorer or conservator of your choice who will be better able to provide a detailed, professional report. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Charles Miller Ltd is merely a subjective, qualified opinion. Prospective buyers should also refer to any Important Notices regarding this sale, which are printed in the Sale Catalogue. NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING A LOT, ALL LOTS ARE OFFERED AND SOLD “AS IS” IN ACCORDANCE WITH THE CONDITIONS OF BUSINESS PRINTED IN THE SALE CATALOGUE.