In the early nineteenth century, David Epstein explains (in Inside the Box), chemists were using different conventions for how they weighed substances, and thus were reporting different weights for the same elements:
The lack of standard practices meant that disagreements on fundamental issues pervaded chemistry. A prominent book listed nineteen notations for acetic acid used by different practitioners. Chemists didn’t even agree on the meaning of basic terms like “molecule.” It was a complete morass—for teaching, and for discovery.
In the summer of 1860, a small group of scientists called for an international conference—the first of its kind—to resolve the confusion. It would be held in September in Karlsruhe, Germany. The location was fortuitous. Twenty-six-year-old Mendeleev happened to be studying abroad in Heidelberg, thirty miles away.
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Cannizzaro made a pitch to revive the fifty-year-old idea from one of his countrymen, Amedeo Avogadro, that if you have equal volumes of gas of different substances, and those gases are at the same temperature and pressure, they will contain the same number of molecules. The old idea was correct, Cannizzaro argued. Just as importantly, using it would allow chemists to compare different substances and arrive at consistent weights for the elements that comprised them. The lone other Italian at the meeting passed out copies of a pamphlet Cannizzaro had created. It explained his reasoning and included a list of weights that chemists should be using for common elements.
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Thirty years later, while giving an honorary speech in England, Mendeleev would recall that day. He recounted how disastrously fragmented the field was at that time, but that Cannizzaro “seemed to advocate truth itself.”
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The creation of standard definitions may seem boring compared to the thrill of discovery. But without consistent weights, Mendeleev’s formidable brain would have stood no chance, and nature’s pattern would have remained hidden. Standardization empowered innovation.
It allowed work to communicate across distance, even if the individuals doing it were not themselves in direct communication. In effect, it made the problem-solving team much, much larger. By 1867, when Mendeleev began to write his textbook, he could rely on the knowledge of weights uncovered anywhere in the world. In a certain sense, the new standards empowered him to collaborate with people he didn’t know.