Here are some of the alternate windshield cleaning methods people employed pre-wipers: Removing the windshield entirely, stopping the vehicle and wiping off the glass before continuing for another 40 feet and doing it again, or rubbing stuff like carrots, tobacco, or onion slices on the windshield to create a water-repellant film (Rain-X, is this your secret?). People also just sucked it up and pretended the rain didn't exist.
Windshield wipers are a simple, common-sense invention, right? Once cars sprouted windshields, it would seem (to our modern sensibilities accustomed to every convenience imaginable), that a priority would be to wipe rain, dust, mud, and errant small animals from the glass with some sort of remote squeegee system. But no, that had to occur to someone (or someones). One someone was James Henry Apjohn, an Irish inventor who patented a device in the U.K. in October 1903 called the "Apparatus for Cleaning Carriage, Motor Car, and Other Windows," proving he didn't have an aptitude for branding.
Also in 1903, another wiper-inventing someone filed a patent: Birmingham, Alabama native, Mary Anderson. The impetus for her wiper design came after witnessing a streetcar operator stick his head out of a two-pane windshield because visibility in the New York winter was terrible.
Instead of huffing indignantly while shivering, Anderson invented and patented a spring-loaded wiper mechanism with rubber blades that would clean windshields in seconds. But rather than hoisting her on their shoulders and handing her all the money, people complained that such wipers would be a dangerous distraction. Nobody wanted to invest in her invention, so she never profited from it. Maybe Anderson should've put her energy toward something more useful, like steering-wheel mounted mechanisms that dispense lit cigarettes.
Another cleaning method was having someone stand on the car's running board to wipe the windshield with a handkerchief, which is what one of the pioneers of automatic wipers tried first. Fred Folberth was driving in the AAA-sponsored Glidden Tour sometime in the 1910s when he hit a downpour. The handkerchief didn't work, nor did applying rain-repelling chemicals to the windshield (they just made a mess once the rain stopped). Folberth and his brother William patented several windshield wiping devices starting in 1919. One design used vacuum pressure from the engine's intake manifold, meaning wiper speed was dependent upon engine rpm. It was less than ideal.
Strangely, Folberth tried and failed powering wipers electrically. Meanwhile, inventor/actress Charlotte Bridgwood had patented electric wipers in 1917 (awesomely called the "Electric Storm Windshield Cleaner") that employed horizontally tracked rollers. Hawaiian dental surgeon Ormond Edgar Wall also patented electric wipers in 1917 that mounted to the center of the windshield and worked like a kid's arms making a snow angel. Neither caught on. Maybe if they'd sneakily hid like C3 Corvette wipers, they would've.
But 1916 was the genesis of possibly the first commercial, mass-production wiper blade. John Oishei, a theater manager, was driving through rain when he struck a bicyclist. The cyclist survived, but Oishei figured if his visibility were better, the accident wouldn't have happened. Searching for solutions, Oishei stumbled upon John Jepson's "Wind-Shield Cleaner," which slid in a central slot between a two-piece windshield. Renamed "Rain Rubber," it was successful enough that Pierce-Arrow adopted it 1919, with Packard, Cadillac and Lincoln following in 1920. After Rain Rubber expanded from North America to Europe, the company rebranded as the Tri-Continental Corporation, better known today as Trico.
In retrospect, it's strange that wipers weren't more immediately obvious. Driving goggles were popular in the early 1900s, and surely no one thought twice about the "distraction" of cleaning them with a spare finger. It wasn't until the 1940s when windshield wipers were even standard equipment, and even then, they weren't necessarily remotely powered. Check out early Willys Jeeps and you'll see manual wipers that required a free hand to operate them. Ideally, you'd have a helpful passenger who didn't mind being set to intermittent (which is not what we mean by "windshield wiper attitude").
Speaking of intermittent wipers, we can't forget Robert Kearns. After getting hit in the eye with a champagne cork on his wedding night, he developed serious vision issues exacerbated when driving during rain. Like most folks, he would blink every few seconds, which gave him the idea to design wipers that did the same thing. He patented a design for intermittent wipers in 1962 and showed them to Ford. Normally, we'd say something like "his idea was allegedly stolen," but there's no allegedly. If you've seen the movie "Flash of Genius" starring Greg Kinnear, you know his invention was very much stolen. Don't worry, he did win millions from lawsuits. Decades later, in the 1990s.
So if you're enjoying a clear, crisp windshield with a set of wipers, take a moment to thank the pioneers, who also include Robert Bosch (yeah, that Bosch), designer of a two-armed system in 1929, and pianist Józef Hofmann, whose allegedly patented wipers were supposedly inspired by metronome action. Otherwise, you could be hanging your head out of the window or scrubbing your windshield with half an onion tied to your belt (which, as Grandpa Simpson says, was the style at the time).