Inventions are a dime a dozen. Truly. The U.S. Patent and Trademark Office just granted patent number 9,000,000 (to WiperFill in Jupiter, Fla, for collecting rainwater from a car windshield and using it in an environmentally sensible way “to replenish fluids in the windshield washer reservoir.” But who knows? In 10 years either every car will have one or none of them will). An even larger number of inventions do not get patented. And that’s not even looking at worldwide creativity. Let’s face it: most of those inventions may sound great, but they are not useful.

But some inventions do make some money and change the world. Inventions never spring into being fully formed. There is a continuum of invention, a process of ever-greater usefulness and practicality. We use the term “invented” to describe a significant milestone on this path of progress. Inevitably there’s some unfairness involved: we usually neglect quite a long line pioneers who came before; then we neglect those who came close to acheiving the same goal; finally, we short-change those who came after and helped turn the milestone into a practical, widely used device. We rarely mention those who mass-manufacture and sell it currently. And bear in mind the context: the invention of the wheel (5,000 to 6,000 years ago) was less important than the invention of the road; the invention of the light bulb may be less influential than the development of home distribution of electricity.

Elisha Graves Otis, for instance, didn’t invent the elevator. He invented the most significant milestone in that continuum in 1854: a safety device. With that step forward, Otis Elevators became a highly successful company (it is still making elevators) and also changed the landscape: when taking an elevator became safe, more people were willing to ride in them and buildings could be built taller. Otis changed the skyline.

So here are some milestones, from 1845 to 1915, on the path to progress of a few inventions that truly changed the world.

A full account of the path to progress, from the founding of the magazine in 1845 to today, is in the Scientific American Archive, at https://www.scientificamerican.com/magazine/sa/