Accession No

1029

Brief Description

spiral logarithmic scale (sometimes called ‘serpentine scale', ‘circles of proportion' or ‘circular slide rule’) and double horizontal instrument, serpentine scale after the design of T. Browne, and double horizontal instrument after the design of W. Oughtred, by John (Johannes) Holland, English, 1650

Origin

England; Cambridge

Maker

Holland, John

Class

calculating; astronomy

Earliest Date

1650

Latest Date

1650

Inscription Date

1650

Material

metal (brass)

Dimensions

diameter 372mm depth 3mm

Special Collection

Provenance

On loan from Trinity College, University of Cambridge from 1951

Inscription

‘Circuli Proportionum Logarithmicj ∞ Johannes Holland fecit, et donauit Anno Dom: 1650 | 1667 ∞’ (obverse)
‘Calorum facies in plano projecta ad
latitudinem celeberrima Academia Cantabrigiensis 52 15’ (reverse)
‘Medium non deserit unquam Cæli Phæbus iter radiis tamen omnia lustrat ∞’ (reverse)

Description Notes

Spiral logarithmic scale (sometimes called ‘serpentine scale', ‘circles of proportion' or ‘spiral slide rule’) & double horizontal instrument, by John (Johannes) Holland, 1650 [with second date, 1667, apparently added later]. Serpentine scale after the design of T. Browne, and double horizontal instrument after the design of W. Oughtred.

Obverse: around the circumference a scale of equal parts divided [0] - 10, numbered by 1, subdivided to 0.01; within this a scale of degrees (uncalibrated), subdivided to 30´; within this a scale of sines (uncalibrated). Within this lies the set of triple logarithmic scales in 11 convolutions, one each for ‘Numbers’, ‘Sines’ and ‘Tangents’. Numbers scale divided 10 - 100, numbered by 1; sines scale divided 5˚ - 90˚, numbered by 1˚; tangents scale divided 5˚ - 45˚, numbered by 1˚. The signature has a later date, 1667, added below the original date.
Reverse: horizontal projection for 52˚ 15´ N (latitude of Cambridge). Degree scale around edge divided [0] - [90˚] - [0] - [90˚] - [0], numbered by 10˚, subdivided to 15´; also marked with the zodiacal sines in the Southern section, and with the cardinal points. Circles of declination drawn from Tropic to Tropic across the equator for every degree except 23˚. Ecliptic drawn and divided to named month, numbered for the Winter months 10-20-28, 30 or 31 as appropriate (presumably would havebeen completed for the summer months), subdivided to 1 day (1st Aries = 10 March). Hour lines drawn for 4 a.m. - 8 p.m., numbered by 1, marked for every 15 minutes.
Central anulus for radial index arm(s) missing.

Incomplete (radial arm missing - not present since arriving at the Whipple)

References

Events