From his Illustrations of Acoustic Surgery (London: Longman, Hurst, & Co., 1825)
The Wellcome Library:
Auroscope (inspector auris) in cross section. Designed and drawn by Thomas Buchanan. Key to components: A) Globular lantern of block tin, with a large door on one side. B) Iron tube, inside polished and secured to lantern. C) Shorter tube made to screw on the end of the tube B. a) Double convex lens, about 3 inches focus, and 3 inches diameter. b) Concave lens to collect rays emitted by d, and transmit them to a, its focal distance the same as a. c) Double convex lens less diameter than a, concentrates the rays at a distance of about 7-8 inches from its surface. d) Candlestick equidistant from a and b. e) Head of lantern, with small oblique holes to let out candle smoke. f.f.g) Pieces of tin prevent rays escaping in these directions. h) Piece of iron into which tube B is fixed. i) Standard made of iron. Bottom is circular and about a foot in diameter.
Buchanan wrote of it: ‘As I intended this instrument solely for the inspection of the meatus auditorius externus, so I have thence called it an Inspector Auris; a term which implies this special use, and for which it will be found well adapted, by all those who may have extensive practice in treating diseases of the human ear.