Accession No

0229


Brief Description

calculigraphe (logarithmic calculator), by H. C., French [attributed], early 20th Century


Origin

France [attributed]


Maker

H. C.


Class

mathematics; calculating


Earliest Date

Jan. 1, 1900


Latest Date

Dec. 31, 1925


Inscription Date


Material

metal (white metal, brass, steel); glass


Dimensions

length 74mm; diameter 53mm; thickness 17mm


Special Collection


Provenance

The accession register records the allocation of this number to “Le Calculimetre” by G. Charpentier from the Hutchinson Collection. The identification of this description with this object seems uncertain.


Inscription

‘H C’ (on one side)
‘CALCULIGRAPHE’ (on other side’


Description Notes

Logarithmic calculating aid in form of fob watch with white metal casing and glazed both sides. One side has circular log scales of sines, numbers and squares running clockwise. Sine scale divided 6 - 90 numbered ‘6’, ‘7’, ‘8’, ‘9’, ‘10’, ‘12’, ‘14’, ‘16’, ‘18’, ‘20’, ‘25’, ‘30’ , ‘35’, ‘40’ , ‘45’, ‘50’, ‘60’, ‘70’, ‘80’, ‘90’; 6 - 20 divided to 10’; 20 - 30 divided to 20’; 30 - 45 divided to 30’; 45 - 70 divided to 1˚; 70 - 90 divided to 5˚. Scale of numbers divided 1 - [10], numbered ‘1’, ‘12’, ‘14’, ‘16’, ‘18’, ‘2’, ‘25’, ‘3’, ‘π’, ‘35’, ‘4’, ‘45’, ‘5’, ‘6’, ‘7’, ‘8’, ‘9’; 1 - 2 divided to 0.02; 2 - 6 divided to 0.05; 6 - 10 divided to 0.1. Scale of squares in two rings divided 1 - [10] numbered 1, 12, 14, 16, 18, 2, 25, 3, 35, 4, 45, 5, 6, 7, 8, 9; 1 - 2 divided to 0.02; 2 - 6 divided to 0.05; 6 - 10 divided to 0.1. Central logo. Line at top of instrument acts as marker across all four scales. Central steel pointer. Other side carries log scale of cubes in 3 circles and scale of equal numbers. Scale of equal numbers divided anti-clockwise [0] - 10 numbered by 1 subdivided to 0.05. Scale of cubes divided anti-clockwise 1 - [10] numbered 1, 11, 12, 13 ... 19, 2, 21, 22, 24, 26, 28, 3, 32, 34, 36, 38, 4, 45, 5, 55, 6, 65, 7, 75, 8, 85, 9, 95; 1 - 2 divided to 0.01; 2 - 4 divided to 0.02; 4 - 10 divided to 0.05. Central steel pointer. Winding mechanism turns front disc anticlockwise. When moved while button on side of instrument is held down, the 2 steel pointers move, one clockwise the other anti-clockwise.

Condition good; complete


References

Mikey McGovern; 'Pocket calculating devices'; Explore Whipple Collections online article; Whipple Museum of the History of Science; University of Cambridge: https://www.whipplemuseum.cam.ac.uk/explore-whipple-collections/calculating-devices/pocket-calculating-devices


Events

Description
This instrument is a calculating aid, that uses the logarithmic scale to simplify complex mathematical calculations.

Invented in 1614 by John Napier, the logarithmic scale is one of the most important developments in the history of mathematics. It is a scale or table of numbers (the logarithms) that simplify multiplication and division to addition and subtraction.

The logarithmic scale has been used on many instruments, most famously the slide rule, this instrument is a variation of the circular slide rule.


FM:40191

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