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