Integraph by G. Coradi

Object Details

Description

This instrument draws the integral of a function that is plotted when the curve representing the function is traced with the tracer. It rests on two German silver rollers attached to a common axle. A framework above the axle carries the tracer arm, the integrating mechanism, and the plotter. A pen point, a pencil point, a calibration bar, a brush, what may be a tracer point and a head for the pencil point are stored in the case.

An inscription on the support for one wheel reads: G. Coradi Zurich. An inscription on the support for the other wheel reads: John R. Freeman (/) No. 121. A paper shed glued to the inside of the lid of the wooden case gives the value in centimeters of the ordinates for curves plotted using different bases.

The integraphs sold by Coradi before about 1903 had a much larger framework surrounding the axle. A similar instrument in the collections of the Science Museum has serial number 173 and dates from 1911. Compare MA.336877.

This instrument may well have been owned by the hydraulic and civil engineer and insurance executive John Ripley Freeman (1855-1932), an 1876 graduate of MIT. Freeman was president of Manufacturer's Mutual Fire Insurance Company of Providence, Rhode Island from the 1890s and also consulted on water power and municipal water supply projects.

References:

Dictionary of American Biography, Supplement 1 (1944).

G. Coradi, Catalogue of Mathematical Precision Instruments, Zurich: Mathematical-Mechanical Institute of G. Coradi, 1915, pp. 27-30. The integraph shown on page 28 is not precisely like this one.

Location

Currently not on view

Credit Line

Gift of Brown University Department of Mathematics

Data Source

National Museum of American History

date made

ca 1910

ID Number

MA.304722.13

catalog number

304722.13

accession number

304722

maker

Coradi, Gottlieb

Object Name

integraph

Physical Description

German silver (parts material)

brass (parts material)

wood (case material)

cloth (lining material)

Measurements

overall: 18.3 cm x 48 cm x 31 cm; 7 7/32 in x 18 29/32 in x 12 7/32 in

place made

Switzerland: Zürich, Zurich

See more items in

Medicine and Science: Mathematics

Mechanical Integrators and Analyzers

Science & Mathematics

Subject

Mathematics

Record ID

nmah_1215070

Usage

CC0

GUID

https://n2t.net/ark:/65665/ng49ca746a5-1453-704b-e053-15f76fa0b4fa