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[[underlined]] Portraits and Iconography [[underlined]] (continued)

Among the specialized holdings are 900 engraved portraits of chemists and physicists.

[[underlined]] Scientific Instruments [[underlined]]

The Dibner gift includes numerous examples of early optical and electrical instruments and devices and laboratory apparatus used by various great scientists. These range from a number of authentic electrostatic generators of the "bottle and brush" and later disk types, the earliest dating from 1740 and ranging through the mid 1800's to a collection of compact portable generators and their ancillary apparatus, such as a Nairne electrical machine for demonstrating the "electric phenomenon" during the latter part of the 18th century, and an excellent collection of Leyden jars.

The collection includes lodestones and combination pocket compasses and sundials of European and Arabic origin, dating from 1550 to the early 1800's, an impressive number of early telescopes, microscopes, surveyors' levels, transits and sextants.

Included in the holdings of electrical apparatus are Morse-type telegraph keys, relays, coils and examples of the Cooke and Wheatstone telegraph systems, together with a large portion of the Groenendijk Collection from Holland--some 150 devices and laboratory apparatus of amateur scientists dating as early as 1777.