Slide rule workshop AC

João's second mystery slide rule

Brzail made circular slide rule

Click images for magnification

Circular slide rule front Circular slide rule back

Data:

  • Circular slide rule with two overlapping discs
  • The upper disc is transparent and has a hairline and also a D scale.
  • It was made to be distributed as a company gift.
  • Made in Brazil.

Questions:

  1. Why was this construction chosen?