The protractor is contained in a paper envelope, which also holds a sheet of instructions written by Penfield. The envelope is imprinted: ARM PROTRACTOR AND GONIOMETER.

The protractor is stored in a blue paper box covered with the company logo and the words BROWN & SHARPE. A label on one end of the lid reads: 510; ORDER BY NUMBER 599-510 (/) BROWN & SHARPE ...

For over 100 years, it has languished while archaeologists debated its function. Now, a physicist has thrown her hat into the ring, arguing that it is the world’s first known protractor.