patent no. 4,118 · g. e. wormwood · 1894
a paper knife that resents being put down
a sprung paper knife of brass and ebony, weighted at the handle so that on release it returns itself to the blotter, blade-down, with a small audible click. wormwood's catch — the patented trip — is tripped by the act of laying the opener down, whereupon a flat spring in the haft snaps the blade flush to the wood.
the use, as advertised: never again a letter knife left across a letter. in practice the catch trips on its own, on the breath of a closed window, on any footstep in the hall. the blade flies shut whether or not a hand is anywhere near it. correspondence remains unopened for weeks.
wormwood died of a quiet wound to the thumb in 1902, having finally taken his own opener apart to study its decision-making. one of the catches was found, on the floor, still cocked.
field-note · keep it on the far side of the desk, behind the inkwell, where the table is steadiest.
apology machine · window signal · silence box · letter · inkpot