Stephen Lehman sent us this wonderful Pentrace link:
"During World War II, the German navy adopted a device called a Schnorchel (often spelled “Schnorkel” in English-language writings), which was a tube that could be extended above the ocean’s surface by a submerged submarine, allowing the submarine to draw in fresh air without surfacing. In 1952, Sheaffer’s Snorkel TM appeared on the market, superseding the very successful Touchdown TM line. The design of the Snorkel is virtually identical to that of the Touchdown, elongated a small amount to accommodate the additional Snorkel filling mechanism. The pen uses a tube like a Schnorchel, but in reverse; the pen’s tube allows the pen to draw in ink without being immersed in the bottle. The most complex filling system ever applied to a fountain pen, the Touchdown-derived Snorkel system was a last-ditch attempt to fight the onslaught of the ballpoint pen, whose great advantage lay in its convenience: no “dunk” filling, reliable writing, and a long write-out. The system works remarkably well, and Snorkels are considered very reliable pens….
…Most pens have Snorkel tubes made of stainless steel (silver or gray colored metal), but some Snorkel tubes were made of a gold-colored metal that appears to be phosphor bronze. The Snorkel tube for a Triumph nib is cut diagonally across its end and oriented so that the open surface aligns with the under surface of the feed. This alignment automatically places the slits in the tube‘s end properly. The Snorkel tube for an open nib is cut straight across its end, but it is still aligned to place its slits correctly. (The lengthwise slit at the end of the tube is nearest the nib, and the two transverse slits are therefore at the sides.) The following illustration shows a Triumph nib with its Snorkel tube extended. You can see the diagonal slits at the sides of the tube’s tip, and you can see the end of the secondary feed that runs the length of the Snorkel tube."
Profile: Sheaffer’s Snorkel
by Richard Binder
Read on at Pentrace