J Halden & Co Ltd 'Calculex' circular calculator, c. 1915, with case and instruction booklet.
Details
- Category:
- Mathematics
- Object Number:
- YL1973.1
- Materials:
- wood (unidentified), metal (unknown), glass, paper (fibre product), leather and brass (copper, zinc alloy)
- Measurements:
-
case: 42 mm x 200 mm x 168 mm,
- type:
- slide rule
- credit:
- Courtesy of Mrs. B.H. Shaw
