In the summer of 1915, a wireless telegraph station in Sayville, Long Island owned by the German company Telefunken was caught sending covert commands to U-Boats patrolling the Atlantic Ocean. The transmission device was recovered, but it still isn't clear what it is or how the messages were sent. The mystery box is in the Henry Ford Museum in Detroit, and though they haven't been able to identify the specific properties of the item, it seems like it should be possible based on the specifics of the machine itself.

The details that are available, plus pictures, are all here, and our site (including details about the project) can be found on the project page. We're hoping a specific identification of the object's mechanism can be determined based on the following clues (from the description pages, above): it is a "light-tight wooden box containing a neon yellow, paper tape reel. When the Museum’s conservation department initially opened the box, the paper tape began fading to a near-white pale yellow, leading them to believe that the tape was treated with cyanide. Kristen Gallerneaux, Curator of Communication and IT at the Henry Ford Museum, first thought of the cyanotype process. But her search for evidence of cyanotype paper-tape devices in radio and wireless history came up with nothing."

Does anyone know of other analogous processes used historicaly similar to the setup described? Are there precedents in the history of covert communications in WWI for non-cyanotype communications methods that might apply to this object?

  • 1
    @SamuelRussell id hazzard this question was asked by philip, as his initials appear to make up prpole's user name.
    – Himarm
    Jan 28, 2015 at 0:27
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    This is interesting but totally offtopic…
    – o0'.
    Jan 28, 2015 at 9:22
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    Thanks for clarifying for me, Himarm, I am one of the coauthors of the article referenced, so of course it does not contain the answers I'm pursuing. It must not have been clear what I was asking for, so I have revised the post. It is as @Samuel-Russell suggests a "feed spool of recording media," but I'm hoping for other historical examples of non-cyanotype transmission/recording processes using cyanide-laced tape. See above for more details.
    – prpole
    Jan 28, 2015 at 16:17
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    We can't really produce our own primary sources here, but the questions about similar things in the history of communications seem to be on-topic. I've made a minor edit to take out any implication of speculation in the question.
    – T.E.D.
    Jan 29, 2015 at 15:15
  • In light of the below, the object wasn't a transmitter after all? Sep 1, 2018 at 17:13

3 Answers 3


The object in question is a blank spool of recording tape for a multiplex photographic recording system. Such systems were commonly used not only at Sayville, but at all transatlantic radio receiving stations. The way the systems worked is that a photographically sensitive tape was fed into a galvanometrically modulated exposer and then immediately developed, essentially making a picture of the Morse code dash-dot sequence received by the radio. This is what a developed tape looked like:

multiplex tape

Here is an example of records of transmissions from various European stations, including the Nauen, Germany, station:

enter image description here

All receiving stations used such systems, not just the German one at Sayville. The example above is from the Bar Harbor station operated by the US Navy, for instance.

The box itself is a light-tight case (notice the red window) in which the undeveloped film is stored on a reel. By opening the box in a lighted room you ruined the film.

  • iow, nothing mysterious at all.
    – jwenting
    Apr 25, 2015 at 6:17
  • Excellent answer. Also, you'll note there is a hole for the exposer mechanism in the upper corner of the case, near where the tensioner spool is inside. The film was likely already light-damaged past the point of recovery with its removal, even before our stalwart historians opened the box. Jul 24, 2015 at 13:51

Here's an excerpt from Kadin2048's answer to this question at ask.metafilter.com, making a reasonable summation if we consider the wire recording (Wiki) techniques that were known at the time:

What I think is more likely, is that the tape was just colored in dark and light patches or stripes, and that it was decoded manually. As the tape went through the 'reader' device, the light reflected from the tape probably just illuminated a window, and a human had to decode it just like they would have decoded Morse code. (The Germans had their own dot-dash code similar to Morse, but not exactly the same.) It was probably itself encoded and meaningless to the person doing the transcription. They would have simply transmitted it onwards, and the final decoding to meaningful instructions would have happened in the actual U-boats.


This looks like the printer for a receiver of high-speed code transmissions, probably marking the paper with electrical impulses. But this is only one component of a system, and might be as little as just the paper feeder.

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