Accession No

6016

Brief Description

reigle platte, calculating rule, a form of Michiel Coignet’s precursor to the sector, possibly Dutch, 1/2 17th century

Origin

Antwerp [possible]

Maker

unknown [after the design of Michiel Coignet]

Class

calculating; mathematics

Earliest Date

1580

Latest Date

1650

Inscription Date

Material

metal (brass)

Dimensions

length 123mm; height 25mm

Special Collection

Provenance

Purchased from Tesseract, Box 151, Hastings-on-Hudson, New York 10706, U.S.A., on 01/12/2004.

Inscription

‘D . Æquales.
D . Graduum.
D . Poly.Æqualiu.
D . Poly.in.Circu.
D . Planoruum.
D . Solidorum.
D . Sinuum.
D . Tangentium.’ (on front side)
‘Eleuationes Poli
D . Sectionum.Glob.
D . Section.Circu.
D . Metallorum.
D. Coprp.regu.
D. Æquales.’ (on reverse side)

Description Notes

This brass reigle platte is a form of Michiel Coignet’s precursor to the sector; 1/2 17th century; probably Flemish and may have come from Coignet’s workshop.

The front side is engraved with nine scales.

The first scale is labelled ‘D. Æquales.’ and is a line of equal parts linearly numbered 10, 20, 30, 40, 50, 60, 70, 80, 90, 100. It is divided with indentations every 1, two indentations every 5 and three every 10.

The second scale labelled ‘D. Graduum’ is a nonlinear line of chords, numbered 10, 20, 30, 40, 50 , 60, 70. It is divided with indentations every 1, two indentations every 5 and three every 10.

The third scale labelled ‘D. Poly.Æqualiu.’ gives the length of a side of a polygon with an equal area to another polygon. It is nonlinearly marked, 10, 9, 8, 7, D, 6, 5, c, 0, Í.

The fourth scale labelled ‘D. Poly.in.Circu’ gives the length of the side inscribed by a polygon. It is nonlinearly numbered 12, 11, 10, 9, 8, 7, 6, 5.

The fifth scale labelled ‘D.Planoruum’ is a line of areas and can give square roots. It is nonlinearly numbered 10, 20, 30, 40, 50, 60 and is divided with indentations every 1, two indentations every 5 and three every 10.

The sixth scale labelled ‘D.Solidorum’ is a line of solids and can give cube roots. It is nonlinearly numbered 10, 20, 30, 40, 50, 60 and is divided with indentations every 1, two indentations every 5 and three every 10.

The seventh scale labelled ‘D.Sinuum’ is a line of sines. It is nonlinearly numbered 10, 20, 30, 40, 50, 60, 70, 80, 90 and is divided with indentations every 1, two indentations every 5 and three every 10.

The eighth scale labelled ‘D.Tangentoum’ in a line of tangents. It is nonlinearly numbered 5, 10, 15, 20, 25, 30, 40, 55 and is divided with indentations every 1, two indentations every 5 and three every 10.

The ninth scale is unlabelled and runs perpendiular to the other scales. It is an arc of a circle, evenly numbered 10, 20, 30, 40, 50, 60, with identations every 5, and five indentations running from 1-5. It gives chords of angles, when the chord and radius have the same length.

The reverse side has a beveled edge at the top.

Below this is an nonlinear hour scale, symmetrically spaced about midday. It is divided by the quarter hour and marked on the hour, left to right, V, IIII, III, II, I, XII, XI, X, IX, VIII, VII.

Below this the eleventh scale, running between XII and VII, is a nonlinear latitude scale ‘Eleuationes Poli’, numbered 30, 40, 50, 60, 70 and divided by 5.

The twelfth scale labelled ‘D. Sectionuum.Glob.’ is used to determine the volume of a segment of a sphere. It is nonlinearly divided by 1 with a single indentation, divided by 5 with two indentations, and by 10 with three indentations. Numbered 5, 10, 20, 30.

The thirteenth scale labelled ‘D. Section.Circu’ is used to determine the area of a segment of a circle. It is nonlinearly divided by 1 with a single indentation, divided by 5 with two indentations, and by 10 with three indentations. Numbered 5, 10, 20, 30.

The fourteenth scale labelled ‘D. Metallorum’ gives the volumes for equal weights of metals. It is nonlinearly marked ‘or, Pl, ar, cu, Fe, St, ma, Pe’ [gold, lead, silver, copper, iron, tin, mercury(?), pewter(?)].

The fifteenth scale labelled ‘D. Corpor.regu.’ gives the length of a side of a platonic solid [or diameter of a sphere] for a constant volume of solid. It is non linearly marked ‘D, I, C, G, O, P’ [dodecahedron, icosahedron, cube, sphere(globe), octahedron, tetrahedron(pyramid)].

The sixteenth scale is labelled ‘D. Æquales.’ and is a line of equal parts. It is linearly numbered 50, 100, 200, 300, 400, 500, 600, 700, 800. With indentations for 1-5, 10, 20, 30, 40, 50, then at every 50.

References

Events