Heriot-Watt University

ICE Scotland Museum

Museum Item : Eidograph


Images: 1: Entire eidograph. 2: Detail of eidograph showing maker's name. 3: Label in side box lid with instructions for setting and adjusting the eidograph.

Item Name: Eidograph

Year Made: c.1870

Description: Eidograph in brass with a circular weighted base carrying a graduated square section brass spar in a sleeve engraved "ADIE & SON EDINBURGH" the spar terminating with two pulleys connected by a steel tape through which pass two further graduated spars carrying at their ends a steel point and pencil.

Purpose: Used for enlarging and reducing drawings. More accurate than the more common pantograph. It can be set to enlarge or reduce in any proportions. The pantograph can only work according to the divisions engraved on it.

Manufactured by: Adie & Son, Edinburgh.

Dimensions (mm): 860 x 840 x 75

Makers Number: None.


Donor: The Corporation of the City of Edinburgh.

When Donated: March 1973

Where Displayed: On display. Museum Area, Case 4: upper shelf.

Sub Items: Fitted case with printed instructions in lid.

Supporting Items: None.

Notes: The ends of the main spar, the pulleys and the other two spars are distinguished by the letters "A" and "B". The scales on all spars are divided into 80 parts to each side of their centres and the verniers on the sleeves within which they slide allow them to be set to 1/10 division. Spars A and B terminate in carriers for the steel point and the pencil and cord operated lever is used to lift the pencil off the drawing paper if required (cord missing). A brass covered lead weight can be set on the main spar. The eidograph was invented by Professor William Wallace of Edinburgh in 1821.

Comments: This item was displayed prior to acquisition at the Institution of Municipal Engineers Centennial Exhibition, Brighton, June 1972. Exhibited at the "Exhibition of Civil Engineering Works", Glasgow, 21 September - 23 October 1977.