Barnes Brothers' constantnometer and ampere rule. Two calculating rules in double-faced watch cases.
Details
- Category:
- Mathematics
- Object Number:
- 1997-1862
- Materials:
- case, card, cloth and calculators, steel, paper, glass
- Measurements:
-
calculator [x2]: 15 x 55 x 80 mm
case: 25 x 165 x 105 mm
- type:
- calculating rule
- credit:
- Tesseract