Abstract: |
Tube in 2 pieces fitting one another. There is a paper scale gummed to the tube, back and front, in two separate strips, one numbered and the other marked only with lines. The intervals are marked without sub-divisions 60, 70, 80, and every 10 to 220. The part of the tube from just below 60 is missing. Top end is open and has been smoothed in flame. |