The Double-Hook Label Standard: A Label That Cannot Turn Edgewise

"The double hook b is composed of two hooks, (see Figs. 1 to 5, inclusive,) formed of the ends of a flexible wire which is secured at the head of or in any suitable position upon the standard a". "When it is desired to use a permanent label, as for trees in botanical gardens, the curved ends of the hooks may be bent over and carried in farther toward the standard or rod a, so as to close the hooks and render the label incapable of being removed save by means of pliers."

**Standards.** Cut two 40 cm lengths of 6 mm mild steel rod and file one end of each to a point. **Hooks.** Cut 30 cm of 1.6 mm galvanised steel wire. With the flat-nose pliers, wind its middle three times tightly round one rod 5 mm below the top so the two ends stand out on either side. Bend each end up and back over into a hook with the round-nose pliers, the hooks 25 mm apart. Make the second standard the same, then cut one hook off it with the cutting pliers. **Labels.** Cut two plates 80 × 50 mm from aluminium sheet with the tin snips, file the corners round and drill two 3 mm holes 25 mm apart near the top edge. Write the plant's name on each with the marker. **Test.** Push both standards into a pot of soil 1 m in front of the box fan and hang a label on each. At each fan setting read the wind speed at the labels with the anemometer, and measure each label's swing from hanging straight with the protractor. Compare with the notebook. Then press the recurved hook ends down toward the rod with your thumb and check the label can no longer be lifted off.

**Frederick Revans Chapman and Clara Jane Chapman** of Dunedin, New Zealand, filed US 551,578 on 8 April 1895; it is dated 17 December 1895. Their standard could be branched at the foot, clipped to a pot's edge or bent at an obtuse angle, and their own label had a brace bent from the plate so the standard held it "at an angle of about forty-five degrees". The double hook took "labels of metal or other substance, such as are now in use", "especially light zinc labels". **Honest limits.** Aluminium stands in for zinc, and the wire is wound, not soldered. The notebook assumes the wind stays square to the label's face, so its swing is an upper bound; the sizes and wind speeds are examples. Your fan readings are the result.