[ArtieBob]

These are circular slide rules. Multipication and division are accomplised by graphically adding or subtracting the values on two logarithmic scales. TSD, altitude corrections, etc.problems can be solved. If you know the basic equations for a particular problem , find the scales labeled with the variables. Constants are predetermined by offsets between the scales. The cursor is used to align values in non adjacent scales. If this abbreviated explanation is not sufficient, come back and I will try to give a specific example.

Best Regards,

Artie Bob