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Box of Planimeters and Supplies

This is a wooden box containing a number of items connected to the use of planimeters in a teaching setting. It includes: A flat black box covered in leather effect material with latches on the front containing a steel planimeter. The planimeter rests on dark blue velvet-covered cushioning which lines the top and the bottom of the box. The planimeter itself is formed of a metal rod, broadly u-shaped with a long base. At one end the metal is formed into a wedge shape, at the other to a conical point. Next to the conical point there is a bracket supporting another rod that extends parallel to the point. Inside the box there is a handwritten note reading: “I find Harling’s hatchet gives better results if I used [sic] the hand on the stem and not the loose handle supplied. JS 24.3.55” The metal planimeter is hand-engraved with the number “407”. A smaller flat black cardboard box with “Universal Soldered Teeth” printed on the top. This contains two metal plate stencils, one of an irregular curved blob, the other in the shape of a hand. Both have small round holes cut in them. The hand is cut of silver-coloured metal, the blob in bronze. Six planimeters in brass-coloured metal, of different lengths. These are all rods formed into a u-shaped, with a broad ‘base’. One end is shaped into a wedge, the other into a conical point. The wedge shape end is divided vertically across the wedge’s half way mark by an engraved line. Affixed to the middle section of the the flat length of the ‘u’ on most of these planimeters there is a raised section with a flat edge, upon which is marked a 4″ long scale scale marked in inches and fine divisions of inches. These are labelled “I.S. Starrett, Athol, Mass. Tempered No. 11” The scale, and the central section of the rod are painted black. The rest of the rod is brass-coloured. Some of the wedges of the planimeters are engraved with a number, such as “33” or “331B” A cylindrical wedge of cork with a number of push pins inserted into it. Two standard 30cm long rulers, made of wood, showing inches and centimeters. One ruler is stamped with “PHYS LAB” Two shorter wooden rulers. One is marked in inches, with fine divisions, as well as an unmarked slanting division. The other is marked in inches and chords of a circle. The second ruler is stuck by some sticky residue to the side of the box. Two broad pencil crayons, one short in red, one long in blue. The blue pencil is marked: “‘AUDITOR’ x Checking Pencil Made in England” Two right angled triangle shapes, both unmarked with scales. One is cut in wood with black rims, otherwise unmarked. The other is cut in yellow plastic, and marked “Acme”. An angle compass in yellow plastic, marked “Keuffel & Esser 50, N.Y.” A thick square metal plate, brassy in colour, with round holes in each corner. Cut into the plate on one side is an indented circle where the edges touch the rim of the square plate, and then smaller concentric circles engraved within that. These are evenly spaced from one another. Large flat-topped cork in tapering cylinder with a pin in it. A number of papers and leaflets. These include: University of Toronto pamphlets labelled “The Hatchet Planimeter”. These include instructions for the use of the hatchet planimeter by a student; a photocopy of a page from a book, also describing the use of a planimeter and related mathematical formiulae; a small booklet with a grey cover entitled “University of Toronto Studies Mathematical Series No. 2 The Hatchet Planimeter, by John Satterly. The University Library: Published by the Librarian, 1921” Handwritten on this booklet is: “For use in the Laboratory (not to be taken away)” The booklet describes in detail the use of the planimeter. Many of the experiments described involve the pieces included in this box. The leaflet notes that “In the Physics Laboratory at Toronto I have in use about fifty of these planimeters”. Also in the box are a number of rolled up bits of paper. Some of these are maps of western Europe, to be used with the planimeters. One is a blank piece of graph paper, by W.G. Pye & Co. The rest are blank pieces of paper, although some have pencil scribblings on.

Also in the box are a number of small handwritten notes.

Accession Number:

Alternative Name:

Primary Materials:

Wood, Metal: Copper Alloy, Metal: Steel, Paper, Card


On a card affixed to the front of the box: “PHYSICAL LABORATORY
The Ansler Planimeter
Book of Instructions
(Corada + our own)
Compasses, Rule, Pins, etc.”

See description for other markings.

Dimensions (cm): Length: 40.7, Width 28, Height:


Planimeters are used to estimate the area of an irregular area.


Very Good: The box is scuffed over its surface, but in good condition. Paper contents are slightly discoloured. Brass planimeters and plate are slightly oxidized across their surfaces; steel planimeter is in excellent condition. Rulers and shapes intact and in very good condition, with only small scratches.

Associated Instruments:,


Various: Box is likely locally made; Planimeters by L.S. Starrett, Athol, Mass & locally made (?); Keuffel & Esser N.Y.,

Date of Manufacture: Various. First assembled c. 1921-1940


Department of Physics, University of Toronto

Additional Information and References:

When this box was located, three objects were removed and catalogued separately:

1) A ledger recording purchases of scientific instruments made by the Department of Physics at the University of Toronto between 1912 and 1934. The ledger was written by John Satterly and is now in the University of Toronto Archives.
2) A closed glass tube in a black case (
3) A compass as from a tangent galvanometer (, labelled with a sticker suggesting a connection to physics Professor J.C. McLennan.

Together these items may represent mementos of the work of Professor John Satterly (worked 1912-c.1953). They may have been assembled by Satterly or assembled by someone else in connection with him. Satterly conducted research on hatchet planimeters, suggesting that this set of instruments held special meaning in connection with him.

Historical Notes:

These objects represent an example of the teaching sets organised by professor John Satterly during his time as Director of the Undergraduate Laboratory at the Department of Physics (1912-1950s). Sets would contain items necessary to conduct a particular experiment or demonstration, or be labelled to provide easy location and organisation of equipment needed for each experiment. This is the only known surviving example. The handwriting on the included labels is Satterly’s.