Wooden Circumferentor by H.S. Pearson (Portland USA) ca. 1810-30

Wooden Circumferentor by H.S. Pearson (Portland USA) ca. 1810-30

Euro 1800

A rare witness of the American history

Circa

ca.1810-30

Country of manufacture

North America

Category: Surveying Instruments & Mining

Description

Wooden Circumferentor by H.S. Pearson (Portland) ca. 1810-30

 A rare wooden American circumferentor (surveying compass).

Signed: “ H. S. PEARSON PORTLAND”

 

Material: wood, paper, brass, glass

Dimension: 34.5cm (13 ½”) long; compass diam. 17cm (6 ¾”); sights 17cm (6 ¾”) high

Condition: good, please note a crack in the back of compass affecting part of the paper card and needle old but not original.

 

The principle of the circumferentor is quite different from the theodolite, where a compass may be used for orientation, but thereafter the scale  remains stationary while an index moves to the sights.

While the theodolite was well suited to surveying a settled landscape with its artificial landmarks of boundaries and buildings, the circumferentor was more appropriate in a survey of undevoloped land, based on the natural magnetic meridian.

Thus the circumferentor became a standard instrument in America.

 

The use of wood is another characteristic feature of early American instruments.

 

Ref.: J.A. Bennett 1992- A decade of accessions. Selected instr. acquired by Whipple Museum between 1980 and 1990.for an identical instrument (n.33)

 

Unknown to S.A Bedini 1964 – Early American Scientific Instruments and their Maker.

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IT Alpha et Omega

Alpha Et Omega

Alpha et Omega is a recently established firm, based in Milan, Italy. We specialise in antique Scientific Instruments and rare Books to supply collections worldwide. Focus is given to optical and time-related instruments, especially before the Industrial Revolution but we are also interested in rare-to-find scientific and natural items and wunderkammer objects. Alpha et Omega also deals in rare books related to Early Science and Scientific Instruments. Please feel free to contact us for individual requests or desiderata.

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