As semesters eventually turn to centuries, universities accumulate a lot of stuff, and they have to figure out what’s what. A science department’s storage facility might be a kind of large junk drawer, holding castoff chemicals, outdated equipment, and specimens in dusty jars—or it might be home to amazing old charts surreptitiously rolled into anonymous scrolls.
Back in 2014, a team tidying a long-languishing storage area in the chemistry department at the University of St Andrews, in Scotland, came across a trove of rolled-up charts. Among those, they found a periodic table. It was printed in German, and it looked old—the creases were deep, the sides were torn, and the paper was prone to flaking.
To gauge its age, the St Andrews team dug into the history of the printer and lithographer, which were identified on the chart. They also recruited Eric Scerri, a science historian and chemist at University of California, Los Angeles. Based on the fact that the table includes gallium and scandium (discovered in 1875 and 1879), but not germanium (discovered in 1886), Scerri concluded that the chart was produced somewhere between 1875 and 1886. “There’s not much else to go on, but that’s a pretty reliable method,” Scerri says. “The elements were discovered over a period of time, and we know when they were discovered. That is a way of nailing it down.”
Scerri suspects that, in its day, a chart like this would have been “reasonably rare”—far from the classroom staple that it is now. “The periodic table didn’t have an immediate impact over chemistry and the way it was taught,” he says. “Like all scientific discoveries, it takes a while to trickle down to the people in the classrooms.”
The Siberian-born chemist Dmitri Mendeleev published his first version of the chart—which organized elements according to their atomic mass—in 1869, accounting for the more than 60 elements known at the time while also predicting and leaving room for ones that weren’t yet familiar to science. A few scientists were noodling over similar ideas at the same time, and while Lothar Meyer, a German chemist, was also laying out a design for a pared-down version of a periodic table (as was the English chemist William Odling), Mendeleev swooped in with a more comprehensive chart and walked off with much of the credit. He updated the table in 1871, and when other elements were indeed discovered over the next 15 years, his work was widely embraced, write Ray and Roselyn Hiebert in the U.S. Atomic Energy Commission’s Atomic Pioneers. Those discoveries, according to Scerri, prompted “people to sit up and take notice,” and helped to land the periodic table in chemistry classrooms.
Eventually, Mendeleev’s eight-column table was replaced by the 18-column one we know today, which also considers atomic structure, instead of just mass. In 1955, a team using the cyclotron in Berkeley, California, bombarded einsteinium with alpha particles and recorded a new element dubbed “mendelevium,” in Mendeleev’s honor.
The St Andrews team secured grants to fix up their fragile chart by removing debris and patching up tears with kozo paper and wheat paste. Coinciding with the 150th anniversary of Mendeleev’s table, the St Andrews find is now stored in the school’s special collections, and a reproduction is hanging in the school of chemistry, for students who get a charge from bits of history almost gone for good.