Circular slide rule
- maker:
- J Halden and Company Limited
Circular slide rule, watch form, in metal case, known as "Halden Calculex", with printed pamphlet of instruction
Details
- Category:
- Mathematics
- Object Number:
- 1921-666
- Materials:
- metal (unknown), glass, velvet, leather and paper (fibre product)
- Measurements:
-
overall (closed): 22 mm x 64 mm x 85 mm, 0.098 kg
- type:
- circular slide rule
- credit:
- Shackleton, M.H.