The Float Inkstand: A Cork That Keeps the Ink From the Air

"It will be seen that the said float will retain its position and operate as a stopper to the ink-tube, until the ink is reduced below the conical part of the float, to the upper line of its base at I, at which elevation the float covers the whole surface of the ink, wholly protecting it from the atmosphere until it is exhausted by use." "One other important advantage of this arrangement is, that at each introduction of the pen, the float is forced down and operates as a loose plunger in removing the sediment, which is ordinarily deposited in the bottom of the stand, and forces it upward and remingles it with the fluid".

**Tube.** Take a glass jar about 45 mm across inside with a metal lid. Drill an 8 mm hole in the centre of the lid and push 25 mm of clear vinyl tubing through it so 20 mm hangs inside. Seal round it with silicone sealant and let it cure. **Float.** Cut two discs from cork sheet, 2 mm smaller than the jar's inside, and stick them together with silicone. Pare the top edge with the craft knife and sand it into a truncated cone whose flat top is wider than the tube. **Fill.** Pour in ink until the float, floating, presses up against the bottom of the tube, and screw the lid on. Dip the pen: it should push the float down and meet ink. **Test.** Fill a second jar to the same level with no float and no lid. Weigh both on the kitchen scale every day for a week and compare the ink each loses with the notebook's area ratio.

**Walter Hunt** of New York, assignor to Augustus T. Arrowsmith, signed US 4,062 on 12 July 1844; it is dated 29 May 1845. He chose cork "in consequence of its lightness, cleanliness and durability", made the reservoir a glass cup under a metal cap holding two pen sockets and the ink tube, and offered an elastic arch of sheet india rubber on the float as an alternative. Hunt later patented the safety pin (US 6,281, 1849). **Honest limits.** A glass jar, vinyl tube and sheet cork stand in for his cup, cap and turned cork. Evaporation only roughly follows exposed area. Cork density is a range and the sizes are examples. Your week of weighings is the result.