“If water be only in contact with fixed air, it will begin to imbibe it, but the mixture is greatly accelerated by agitation, which is continually bringing fresh particles of air and water into contact. All that is necessary, therefore, to make this process expeditious and effectual, is first to procure a sufficient quantity of this fixed air, and then to contrive a method by which the air and water may be strongly agitated in the same vessel, without any danger of admitting the common air to them."
Joseph Priestley had a lot of unusual ideas. As a clergyman and philosopher in the late 18th century, his theological notions (he wrote that the Anglican Church, and its teachings, were a corruption of Christianity) got him rioted out of Birmingham. As a scientist, he was interested in what exactly air was made of—but even as he discovered gases like nitrous oxide and, most famously, oxygen, he was also drawn to a theory of fading scientific relevance that attributed flammability to a (nonexistent) special element called phlogiston.
But among his unusual ideas, Priestley lit on one discovery that endured in both popularity and profitability—he figured out how to make carbonated water.
At one point in his career, Priestley lived near enough to a brewery that he had started investigating the airs that its fermenting beer gave off. And he noticed that the water, left above the brewer's mash, would take on a flavor not unlike much-valued, naturally occurring mineral springs. This water was absorbing the carbon dioxide—what Priestley called "fixed air."
Soon, he had come up with a more efficient method of mixing air with water. The idea was simple enough, he wrote in 1772:
Here's how Priestley did it. He filled a bottle "with a pretty narrow neck" with water, put a piece of paper on it, turned it upside-down and put it in partially filled bowl of water. He removed the piece of paper from the invented bottle and snuck in a piece of flexible piping. That piping led to a bladder (an actual animal bladder), which on the other end could be connected, via a cork with a hole in it, to a second bottle filled with chalk and a little bit of water.
To force fixed air into water, Priestley explained, all a person had to do was add "oil of vitriol" (a.k.a. sulfuric acid) to the second bottle and stick in the cork. Shake that bottle to create fixed air, and when the bladder had filled up, press the air through the piping and into the inverted bottle. Eventually, half that bottle would be filled with gas (the water having been pushed out into the bowl.
The last step: Put your hand on top of the bottle, and shake until the air and water mix. (Repeat the whole procedure until the water's saturated.)
It was time-consuming and, some detractors claimed, the product tasted a bit like urine, due to the bladder's involvement. But it had potential—the British Navy, believing the bubbly water could prevent scurvy, was interested in sending bottles out with its sailors. And within a decade, inventors in Britain and in Europe had taken Priestley's basic idea—get some "fixed air," mix it with water, shake—and created contraptions that could make carbonated water more quickly, in greater quantities.
One of those inventors was named Johann Jacob Schweppe, who sold bottled soda water and whose business is still around today. But wealthy Europeans had preferred fresh soda water: It was common for households that could afford it to acquire a version of Nooth's Apparatus—what the writer Tristan Donovan, in his book Fizz, calls "an eighteenth century SodaStream"—which could make soda water on demand.