Accession No

1393

Brief Description

omograph, 2/2 19th C

Origin

Maker

Class

mathematics (?)

Earliest Date

1850

Latest Date

1900

Inscription Date

Material

wood (ebony, 2 other types); metal (brass, oxidised brass, at leas 1 white metal); cloth (felt); paper (card and one other); graphite; hide (leather)

Dimensions

length 430mm; breadth 160mm; height 180mm box length 494mm; breadth 225mm; height 284mm

Special Collection

Cavendish collection

Provenance

Transferred from the Cavendish Laboratory, University of Cambridge.

Inscription

‘OMOGRAPH FOR
COMPOUNDING “SINE” CURVES
bequeathed to the
UNIVERSITY of CAMBRIDGE
by
SIR THOMAS WRIGHTSON, BT.
author of
“MECHANISM of the INNER EAR”’ (brass plaque on box)

Description Notes

Rectangular wooden base with brass plate supporting series of rollers and gears. Ebony-handled crank turns toothed brass wheel which drives a second cog which is connected to a brass disc by a white metal axle. This brass disc carries an offset pin which couples to a horizontal bar, which moves backwards and forwards as the disc is turned. A second disc and bar are driven directly by the handle. The handle also drives the uppermost veneer-covered roller. Brass roller beneath this turns through friction. Another wooden roller is mounted towards the front of the base and turns freely. Three brass pencil holders carried between the two horizontal bars.
Fitted wooden case with leather carrying handle, partially lined with green felt. Drawer below main cavity contains spare gear wheels (all gear wheels marked with a ratio), box of pencil leads (only one present) by Reeve & Sons, rolls of blank paper and blueprint for instrument. Front of box is removable and slots into the main part by brass lugs; brass lock (no key).

Condition good (leather of handle perished); complete.

References

Events