watch-glass

British  

noun

1. a curved glass disc that covers the dial of a watch

2. a similarly shaped piece of glass used in laboratories for evaporating small samples of a solution, etc

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Example Sentences

Hollowed out; the inner surface of a watch-glass is concave, and may represent the form of a concave mirror, or lens.

From Conversations on Natural Philosophy, in which the Elements of that Science are Familiarly Explained by Jones, Thomas P.

Without washing, transfer the film to a watch-glass containing the reducing solution and allow it to remain therein for from thirty seconds to one minute; blot off the excess of fluid with filter paper.

From The Elements of Bacteriological Technique A Laboratory Guide for Medical, Dental, and Technical Students. Second Edition Rewritten and Enlarged. by Eyre, J. W. H. (John William Henry)

At the end he found himself the richer by— A watch-glass.

From The Astonishing History of Troy Town by Quiller-Couch, Arthur Thomas, Sir

A watch-glass is warmed, and a layer of wax is melted over the convex side.

From A Text-book of Assaying: For the Use of Those Connected with Mines. by Beringer, Cornelius

When a piece of plate-glass is pressed against a slightly convex lens, or a watch-glass, a series of coloured rings is formed by reflected light, with a black spot in the centre.

From Heroes of Science: Physicists by Garnett, William