One of the most famous letters ever written in English is called the Bixby Letter. The story goes that in November, 1864, John A. Andrew, governor of Massachusetts wrote to President Abraham Lincoln asking him to send a note of condolence to Boston mother Lydia Bixby, whose five sons were reportedly killed during the Civil War. The President complied, penning a 139-word missive that made its way into the Boston Evening Transcript. The succinct note was reprinted across the North, and the final line served as a balm to families mourning soldiers across the country. “I pray that our Heavenly Father may assuage the anguish of your bereavement, and leave you only the cherished memory of the loved and lost, and the solemn pride that must be yours to have laid so costly a sacrifice upon the altar of freedom.”
But since its publication, scholars have argued whether the letter was really written by Lincoln or by his private secretary John Hay, a talented writer himself who went on to become an ambassador and Secretary of State. Now, a new study hopes to put that controversy to rest. Using a technique called n-gram tracing, a group of researchers have concluded the letter was “almost certainly” written by Hay, reports Lily Rothman at TIME.
The letter has been universally admired over 150 years, with famed journalist Henry Watterson calling it “the most sublime letter ever penned by the hand of man.” Its quality is the least controversial thing about it. Michael Burlingame, writing in the Journal of the Abraham Lincoln Association, reports that Bixby had in fact lied about the death of her five sons. While two of them died in battle, one was honorably discharged, one deserted for certain and the fifth may have deserted. It also turns out Bixby was likely sympathetic to the Southern cause, and hated President Lincoln. Burlingame reports that the original letter was either destroyed by Bixby soon after receiving it or was tossed out by the Evening Transcript after publication.
In the 1920s, Burlingame reports that claims Hay wrote the letter began to surface, including multiple reports that Hay admitted he wrote the letter to several confidantes but asked that no one to reveal the fact till after his death, which happened in 1905. Since then, the letter has had a historical asterisks next it, with scholars arguing for and against Hay’s authorship.
That’s why the team from the University of Manchester decided to analyze the letter. While current forensic techniques are pretty good at determining the authorship of longer pieces of writing, short blurbs like the Bixby letter are much more difficult to figure out. “Often, historical cases of disputed authorship involve very long texts, and there are several well-tested techniques that can be employed to solve these problems,” Andrea Nini, a member of the team, says in a press release. “Because of its shortness the Bixby letter presented many challenges, and we had to devise a completely new method to analyse it.”
According to Rothman, the team used a variation of its n-gram technique to study the letter. Previously, in 2013, the group of forensic linguists used n-grams to reveal that mystery writer Robert Galbraith was a pseudonym for Harry Potter scribe J.K. Rowling.
Rothman explains that the sequencing technique breaks down texts into tiny chunks, for instance a bigram is a sequence of two, a tri-gram is a sequence of three, and so on. The n-grams can be used to detect pattern in words or broken down to detect patterns in groupings of letters. Jack Grieve, who also worked on the project, tells Rothman that over time each person develops a very subtle, unique way of writing called an idiolect, which is like a hidden fingerprint. “We pick up these idiolects over our lifetimes, not just because of where we grew up, but where we went to school, what kind of job we do, our personal history,” Grieve says.
A computer algorithm can look at n-grams and find these idiolects in even short texts. Using that method, the researchers decided to look at 500 texts known to be written by Hay and a similar number written by Lincoln. They then set the algorithm loose on the Bixby letter. In 90 percent of the n-gram variations examined, Hay came back as the author. The other 10 percent were inconclusive, but most of those were based on very common n-gram groupings of just one or two letters, not entire words.
The research has been submitted to the journal Digital Scholarship in the Humanities. Though it remains to be seen if the forensics community will accept the new technique, that’s not stopping Nini. According to the press release, she plans to use n-grams to examine letters to try and finally unmask Jack the Ripper.