The Cartographer of the Unseen: On John Graunt and the First Death Ledger
Long before the term 'open data' was coined, before servers hummed in climate-controlled rooms, a London haberdasher named John Graunt performed an act of radical digital preservation. His medium was not silicon but paper; his dataset, a mountain of handwritten weekly Bills of Mortality. In 1662, Graunt published his 'Natural and Political Observations... upon the Bills of Mortality,' and in doing so, he didn't just analyze data—he created the very discipline of demography and gave us a blueprint for reading the stories hidden within public records.
The Bills themselves were a primitive form of civic data collection. Parish clerks, often ill-educated 'Searchers of the Dead,' would inspect corpses and record causes of death with grimly poetic labels: 'rising of the lights,' 'teeth,' 'king's evil.' It was raw, messy, and deeply flawed data, rife with the biases and superstitions of the era. Most Londoners viewed these Bills as mere morbid curiosities or a crude indicator of whether the plague was worsening in their neighborhood. They saw the trees; Graunt saw the forest.
What makes Graunt a patron saint of open data isn't the perfection of his source material, but his methodology. He took 50 years of these fragile, ephemeral documents—each week's bill a candidate for being lost, discarded, or used to wrap fish—and preserved their essence not by locking them away, but by aggregating, counting, and questioning. He cross-referenced, he estimated populations, he identified statistical patterns. He was, in effect, running a manual, human-powered algorithm on the city's public health data.
His most profound insight was a corrective to the noise. He realized the Searchers' habit of attributing most unknown ailments in the elderly to 'aged' was obscuring true causes. By critically assessing the data's provenance and its collectors' limitations, he adjusted his analysis, striving for a clearer signal. This critical interrogation of a dataset's integrity is a ritual every modern data scientist and archivist would recognize instantly. He wasn't a passive collector; he was an active, skeptical interpreter.
Graunt’s work reminds us that the heart of open data and digital preservation isn't the sheer act of hoarding bytes. It is the deliberate, thoughtful process of making raw information legible, of finding the narrative in the numbers, and of preserving not just the record itself, but the meaning we can glean from it. He built a lasting archive of insight from the most temporary and grim of documents, mapping the unseen forces that shaped a city's life long after the ink had dried.
Notes & further reading
A few pages I came back to while writing this: