Thomas Edison was recognized throughout his career as one of the most influential inventors of all time, but few idolized him like automotive pioneer Henry Ford.

In 1896, when the young Ford was still just an engineer in the Edison Illuminating Company of Detroit, Edison encouraged him to follow through on his pet project—adapting the gasoline combustion engine for cars.* Ford did, of course, and by the early 1910s, the two had become close friends. They exchanged ideas, went camping together...Ford even bought an estate close to Edison’s in Florida so that the two could “winter” in the same place.

And so perhaps it isn’t so surprising that, when a single glass test tube showed up among some of Edison's personal effects at the museum Ford established (originally named the Edison Institute), curators would assume that Ford may have commissioned the retrieval of his friend’s last, dying breath.

After all, Ford collected a lot of Edison artifacts for posterity and had orchestrated a facsimile recreation of the inventor’s Menlo Park, N.J., workshop on his own estate outside Detroit. And when the tube was discovered in 1978, a note was reportedly attached, written by Edison’s son, Charles, stating: “This is the test tube you requested from my father’s bedroom.”

So, upon Edison’s decline in 1931, was Henry Ford really so infatuated as to ask a son to capture in a bottle his father’s last mortal gasp?

Not so much.

Though some linked the momento mori to Ford's interest in reincarnation and his supposed belief that the soul escapes the body with its last breath, Henry Ford Museum curators have a more earthly explanation, thanks to a letter discovered in the late 1980s. In it, Charles Edison, writing in 1953, explains that the tube of death-breath was a gift and not specifically commissioned by Ford:

During Mr. Edison’s last illness there was a rack of eight empty test tubes close to his bedside. They were from his work bench in the Chemical Room at the Laboratory in West Orange. Though he is mainly remembered for his work in electrical fields, his real love was chemistry. It is not strange, but symbolic, that those test tubes were close to him at the end. Immediately after his passing I asked Dr. Hubert S. Howe, his attending physician, to seal them with paraffin. He did. Later I gave one of them to Mr. Ford.

Today, the test tube—still sealed—is displayed in a case just within the front doors of the Henry Ford Museum in Michigan. It is one of the only artifacts of its kind, a reminder of both a friendship and the fleeting mortality of even the most successful men.

*This sentence has been updated for accuracy.