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Glass Slides Depicting Concentric Circles


This object consists of a blue repurposed jewellery box containing five glass slides wrapped in a scrap of paper. The jewellery box is from Ryrie & Birks and has a larger lid, hinged that opens on a smaller base. The inside of the lid contains a satin-like lining.

The five slides are all roughly square in shape, although differing in size from around 4cm square to 1.5cm square. Each has a square image of regular concentric circles in the centre. The centre rings are wider, and there is a large space in the centre of each pattern which does not contain circles. On the four smaller slides, the circular pattern is centred in a black surround; on the larges the slide, the circular shape overlaps the edges of the exposed edges. The slides appear to have been cut down to size by hand. One of the slides has a border formed of cut stickers taped around the edge of the pattern.

A scrap of paper used to wrap the slides is lined on one side. On the unlined side, there are handwritten equations in ink.

Accession Number: 2019.ast.196

Alternative Name:

Primary Materials: Plastic, Fabric, Glass, Paper


On the inside of the storage box: “RYRIE ~ BIRKS

Dimensions (cm):

Box: Length = 11.5, Width = 6, Height = 4



Good: The box is in good condition with some small signs of wear on the corners. The images on the slides are in good condition; however, the surrounds to the images are in some cases peeling away from the glass. The paper used to wrap the slides is very worn and torn along the edges. All five of the slides are crudely cut.

Associated Instruments:

Manufacturer: Locally made

Date of Manufacture: Mid 20th Century


These slides were likely made at the David Dunlap Observatory and may form part of someone’s research or project. They were kept at the Observatory until 2009 when upon the sale of the Observatory they were moved to the University of Toronto’s Department of Astronomy & Astrophysics at the St George Campus. In 2017 they were moved to a new storage location in McLennan Physical Laboratories.

Additional Information and References:

Historical Notes: