Proportional compass
Date1761
Inventory NumberDW0367
ClassificationProportional compass
Subject
Maker
Jacques Canivet
fl. 1743 - 1774
Cultural Region
Place of Origin
Dimensionscompass closed: 24.2 × 1.3 × 2.4 cm (9 1/2 × 1/2 × 15/16 in.)
case: 27 x 2.5 x 3.5 cm (10 5/8 x 1 x 1 3/8 in.)
case: 27 x 2.5 x 3.5 cm (10 5/8 x 1 x 1 3/8 in.)
Material
Accessoriescase
DescriptionThis proportional compass is made of brass with steel points. It has a brass cursor that slides up and down the two legs and a wing nut to lock it in position. The scales on both arms are for dividing a line into equal parts. The positions for the cursor are given in terms of fractions:
arm a
1/2, 1/3, 1/4, 1/5, 1/6, 1/7
arm b
7/8, 6/7, 5/6, 4/5, 3/4, 5/7, 2/3, 5/8, 3/5, 4/7, 3/7, 2/5, 3/8, 2/7
The case is made of wood covered with leather given a poppy-seed finish (to make it appear as sharkskin). It is lined with green parchment and red velvet. It has a slide-on top.
arm a
1/2, 1/3, 1/4, 1/5, 1/6, 1/7
arm b
7/8, 6/7, 5/6, 4/5, 3/4, 5/7, 2/3, 5/8, 3/5, 4/7, 3/7, 2/5, 3/8, 2/7
The case is made of wood covered with leather given a poppy-seed finish (to make it appear as sharkskin). It is lined with green parchment and red velvet. It has a slide-on top.
Signedon one arm: Canivet à La Sphére à Paris. 1761.
Curatorial RemarksXRF analysis of the metals was done by Katherine Eremin and Sara Schechner in August 2007.
FunctionA proportional compass is used to divide a given line into any number of equal parts.
ProvenanceDavid Wheatland purchased from Alain Brieux, Paris, August 6, 1968 (lot 32/3). Donated to CHSI 1985.
Jacques Senecal
Date: circa 1680
Object number: 7389
Harvard Cyclotron Laboratory
Date: 1947-2002
Object number: 2003-1-0291
Jacques Senecal
Date: circa 1680
Object number: 7388
Pickett & Eckel, Inc.
Date: copyright 1959
Accessories: brown leather case with hard plastic lining and flap closure; small plastic bag; Twin Pack box; 3 instruction manuals (in file); belt loop (1991-4-0004b); pocket slide rule (1991-4-0004c); cardboard box
Object number: 1991-4-0004a
Jacques Guerard
Date: mid 17th-late 17th Century
Object number: 7507
Date: 1890-1930
Object number: RS0501
