Scientists read a 300-year-old sealed letter without opening it – CNET [CNET]

March 3, 2021 Thomas Giboney technology

Letter opening — Scientists are using technology to read centuries-old letters sealed using “letterlocking.”

Nature Communications

The contents of a handwritten European letter sealed for 300 years are no longer a secret, thanks to a technique that let scholars peek inside virtually without damaging the intricately folded historical document.

In the letter, dated July 31, 1697, Jacques Sennacques asks his cousin Pierre Le Pers, a French merchant in The Hague, for a certified copy of a death notice for Daniel Le Pers. That’s no history-making revelation, but the technique that revealed the request could hold promise for unlocking sealed correspondence containing historical gems across time and place.

All those years ago, Sennacques’ letter was closed using a process called “letterlocking,” a complex folding technique used globally to secure post before the invention of envelopes. Think of it like ancient encryption: Letters sealed this way couldn’t be opened without getting torn, and rips indicated a note had been tampered with before reaching the intended recipient.

“Letterlocking was an everyday activity for centuries, across cultures, borders and social classes,” said Jana Dambrogio, the Thomas F. Peterson Conservator at MIT Libraries and one of the authors of a paper published Tuesday in the journal Nature Communications that details the virtual unlocking technique.