Hemmi 150

Note

This rule is Hemmi's first duplex rule which was first offered in 1931. Its design is a copy of K & E's No.4088-3.

The original owner of this specimen must have been an avid slide rule user. He had curved-in numerous scales by hands. The extensions for C and D scales were also curved by him. From Chinese characters curved-in, such as "Volatile" and "Oil", I assume he was a petrochemical engineer.