In July 1697, Jacques Sennacques of Lille, France, sent a letter to his merchant cousin, Pierre le Pers, in The Hague. The topic of discussion was a death certificate for their relative, a topic that cousins had previously discussed, but Pers neglected to pursue. The letter was the equivalent of a Renaissance “on my previous e-mail” and was read only for the first time since it was sealed 324 years ago.
But even though it has been read, the letter remains unopened. It’s letterlocked, a term coined by MIT conservative Jana Dambrogio for letters that use specific folds and slits to seal without the need for an envelope. Letterlocking it was the typical way to seal messages in the days before mass-produced envelopes; Queen Elizabeth I of England had at least five different options for blocking letters to privatize her correspondence.
In a unique application of technology, Dambrogio’s team “unfolded” Sennacques’ epistle using virtually X-ray microtomography, which allowed researchers to circumvent the often harmful process of manually opening letters. The team’s research was published on Tuesday in Nature Communications magazine.
“I remember a feeling of exaltation, as in, [oh my god] I finally did it, ”co-author Rebekah Ahrendt, a musicologist at Utrecht University, said in an e-mail. “After working with this collection for a few years, the ‘I’m probably the first person to read this since it was written’ effect is a bit exhausted … That being said, this letter is such a wonderful example of people’s concerns. normal at this time. ”
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It is not known why Pers never received the letter – given his profession, he may have moved. But the sealed letter remained in the care of Hague postmasters Simone de Brienne and his wife, Marie Germain. The couple did not throw the family matter closed, because in those days the letters were bought by the recipients, not paid by the senders. Some postmasters kept unclaimed letters in case someone came to buy them. The couple in charge of the Hague post were either a treasure or determinedly optimistic, because they kept the letters until they died. Thousands of letters under the accusation of Brienne and Germain have been kept in an old trunk, and 600 of them are unopened, blocked messages; is an amazing ensemble of European conversation suspended in time, now called the Brienne Collection. The collection is in the Hague Museum of Sound and Vision.
The X-ray drawing through the letter written by Sennacques led to the spread of the iron-rich ink that he noted in each box in the letter. The intensity of the X-rays was about a third of those used by the same machine for its original purpose – images of teeth and bones.
“We start with a very high-resolution CT scan of the folded letter packet, basically a 3D X-ray image,” said co-author Amanda Ghassaei, the project’s lead algorithm engineer who previously worked on the simulation. folds in origami, in an email. “From there, our algorithm detects individual layers of paper in the scan and reconstructs the folded geometry. This calculation pipe allows us to observe the writing, watermarks, seals, internal folds and any other information hidden inside the package of letters, without affecting the original artifact. ”
But that was not enough. The team also had to decrypt the folded letter, understanding which characters fell into the unfolded version. To do this, they used a flattening script, to deconstruct the letter without touching it. Although an imperceptible mixture of characters from outside, wrapped in khaki newspaper, the research team managed to extract the message without problems.
The research team did not describe any folded aspect of Sennacques’ letter in the code; the algorithm raised the geometric weight.
“The message and the complicated internal mechanics of these letters are known to us only because they were practically reconstructed,” said co-author Holly Jackson, an MIT student and algorithmic engineer on the project. “Our methods are fully automated, unbiased for scanning orientation and do not require prior knowledge of the folded geometry of a package of letters.”
So, to create the new work, the team used X-rays to detect the appearance of ink on a century-old piece of paper, built and implemented an algorithm to unfold that virtual paper, and described the contents of that letter along with a complex dictionary for various letter-blocking techniques as a greater practice in the days before envelopes. In essence, the work was threefold.
The sum of these efforts is a clear plan of attack for about 600 objects locked with letters that remain in the chest. Summer calms, marital disputes, state secrets – who knows?
It’s how close history can be to holding your breath.