2023 Author: Bryan Walter | [email protected]. Last modified: 2023-05-21 22:24
Scientists used an X-ray microtomograph to read multiple folded letters from the Brienne collection without opening them. Thus, it was possible to read, for example, a letter from Jacques Sennac, specially folded and written in 1697. The new method allows you to study not only the text of the letter, but also how it was protected from being read on the road. The research results are published in the journal Nature Communications.
Until the thirties of the 19th century, envelopes were not widely used in the postal business. To protect against unauthorized reading, the senders folded a sheet of paper into an envelope, but there was no general folding technology. The burden of paying for postage lay on the addressee, and therefore the mailmen that did not arrive (for various reasons) were mostly destroyed by the postmen, however, the postmen of the 17th century Simon and Maria de Brienne did not lose hope of paying for their work and accumulated them, hoping for late payments - thus we have received thousands of letters.
Examining old letters folded in this way is a daunting task. This is primarily due to the fragility of old paper, which will break at the folds when you try to unfold the letter. A chest from the Brienne collection is in the Museum of Communications in The Hague; it contains 3148 items that never reached their addressees. Of these, 2571 are open letters, and 577 are closed mailing lists. In 2015, a team of researchers undertook to decipher, founding the "Signed, Sealed, and Undelivered" project.
This year, researchers led by MIT's Jana Dambrogio presented their first results. They analyzed many old letters and created a system for classifying their protection. To analyze them, you usually have to open sealed letters, compromising their integrity. Therefore, the scientists decided to use the method of X-ray microtomography to obtain a three-dimensional picture of rolled sheets of paper without opening them.
Layer-by-layer scanning of a batch of ten letters
In order to automatically analyze the text of the letter, the authors have developed an algorithm. With the help of X-ray microtomography, volumetric mapping of a folded letter is carried out, the ink contains elements with a large atomic number, and therefore more scatters X-rays, which is expressed in a bright glow. Then the surface of the letter is reconstructed using an auxiliary grid. To clarify the position of the folds, the scientists built a curvature map - this made it possible to reproduce the process of sealing the letter.
The researchers selected a sealed letter numbered DB-1627 as one visual virtual disclosure. Inside a letter dated July 31, 1697, Jacques Sennac (royal councilor in the city of Lille) asks his cousin Pierre le Perce (a French merchant in The Hague) to send a confirmed copy of Daniel le Perce's death certificate.
English translation of letter text
Dear sir & cousin, It has been a few weeks since I wrote to you in order to ask you to have drawn up for me a legalized excerpt of the death of sieur Daniel Le Pers, which took place in The Hague in the month of December 1695, without hearing from you. This is f… g I am writing to you a second time in order to remind you of the pains that I took on your behalf. It is important to me to have this extract you will do me a great pleasure to procure it for me to send me at the same time news of your health of all the family. I also pray that God maintains you in His Sainted graces & covers you with the blessings necessary to your salvation. Nothing more for the time being, except that I pray you to believe that I am completely, sir and cousin, your most humble & very obedient servant,
I beg you to send your response to Mr Sennacques, king’s councilor in the bailiwick of Lille, Rue St Etienne in Lille ´
From Lille, the 31st of July 1697.
Letter from Jacques Sennac of Lille
Also, using their algorithm, the scientists managed to virtually deploy three more letters (DB-1538, DB-1976 and DB-2040), which demonstrates the versatility of the new method. For letters with a separate written lock (for this, a hole was made in the letter through which a piece of paper sealed with a seal was threaded, such a letter could only be opened with a cut), the researchers managed to visually separate the letter and the lock. To check the result, one of the letters was opened - the discrepancies between the virtually expanded letter and the real one were extremely small.
Letter DB-2040 that was opened for verification
The authors characterized the closed letters depending on the manipulation of them: folding or folding, folding, making a gap or hole, sealing with sealing wax or a written lock. When analyzing 1706 open letters with similar protection from the Brienne collection, scientists found seven types of letters among them: 58 rectangular, 1473 wide rectangular, 139 extra wide rectangular, 22 long rectangular, 10 square, 3 diamond-shaped and 1 pentagonal. When evaluated visually, it might seem that the DB-1976 letter can be either easily defended or difficult. However, with a virtual scan, it turned out that it would not have been so difficult to open the letter. Probably, one of the purposes of the manipulation of the letters was to intimidate the interceptor that he would not be able to accurately reproduce all the details.
In the future, the researchers plan to improve the algorithm for converting large letters to flat letters. With the help of X-rays, it is almost impossible to detect pencil notes and carbon ink (if the dye practically does not differ from paper in its elemental composition). In addition, it is necessary to change the algorithm for human intervention along the way - it is because of this that the torn areas on the scanned letters turned out. The next goal, after analyzing and unpacking all the letters in Brienne's collection, the authors put 160 thousand trophy letters confiscated by the British Empire from enemy ships.
The letters from the Brienne collection were sent more than three hundred years ago - however, such letters are not uncommon in the archives. Another thing is letters in a bottle, which are found centuries after they were sent. To date, the record of 138 years of sailing was set three years ago - a letter was discovered in Australia from a German ship, which was thrown into the sea to study ocean currents at the end of the 19th century.