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Cup Anemometer (Casella)


A wooden case with a latch and leather handle contains an anemometer consisting of two main components as well as an instruction leaflet and other documents.

Clamped in a wooden bracket inside the case is a component that is composed primarily of a translucent white plastic sphere. An electrical cable emerges from a mounting bracket at the top of this sphere. This component is held in place with a latch.

A second component (a “cup rotor”) is held on a second bracket within the case. When the instrument is assembled for operation, this rests on a pointed spindle on the first component. 

The case also contains the following documents:

– An instructional leaflet labelled “Sensitive Anemometer and Battery Charger”
– A sheet of graph paper with printed data of anemometer readings. This information is undated. 
– Two laminated sheets Labelled “Sensitive Anemometer No. Standard  No. 1” and “Sensitive Anemometer No. Standard  No. 3” respectively. “Sensitive Anemometer No. Standard  No. 2” is printed on the reverse side of the first sheet. 

Accession Number: 2023.zoo.88

Alternative Name:

Sensitive Anemometer and Battery Charger

Primary Materials: Wood, Steel, Plastic


The first component has the following number embossed on a small silver label on the surface of the plastic sphere: “2405”

The instruction leaflet includes the following information:
“Instruction Leaflet 3106/AA/1”
“Sensitive Anemometer// Ref: T 16108/1 Leaflet 933/1”

Dimensions (cm):

Case: Height = 11, Width = 23.5, Length = 3.


This is a sensitive cup anemometer used to measure low speed airflows. It incorporates a cup rotor that is clamped to a spindle. Attached to the spindle is an opaque disk that is housed within the spherical enclosure. Half of the disk’s circumference is transparent. The rotation of this disk is measured based on alternate light and dark periods detected by a photocell.


The instrument is in good cosmetic condition. The surface of the wooden case is nicked and scratched, especially on the outer surface of the lid. The leather handle has split (delaminated). There is a white corrosion on the connectors of the electrical cable and on three nuts attaching the cup elements of the cup rotor to the central spindle. There is a brown stain on the sheet of graph paper with printed data of anemometer readings.

Associated Instruments:


C. F. Casella & Co. Ltd., Regent House, Britannia Walk, London, UK

Date of Manufacture: c. 1960s to 1970s


This artifact was acquired from Greg Mrychko of University of Toronto Facilities and Services on Friday, August 25th, 2023.

A second example of this instrument (2023.zoo.89) includes a document listing the name of Dr. James Bruce Falls (b. 1923) of the University of Toronto Department of Zoology.

Additional Information and References:

The Science Museum Group catalogue lists an earlier model of this instrument dated 1950. (Entry archived on Friday, August 25th, 2023.)

Historical Notes:

  • Donated to UTSIC