Steam would be considered a gas. Benjamin Franklin concluded from his many experiments, that electricity had certain properties, such as pressure, current. He further concluded that it s movement was predictable, like the pouring of water from one glass to another. From his conclusions, it was conventionally assumed that while we might not be able to SEE electricity at work, we could see it s effects. And electricity, like unto water, acted like a fluid in every sense of the word.
All matter then takes up space.
And anything that takes up space can be broken down into smaller pieces. A solid block of wood may be cut into smaller pieces until it is toothpicks, splinters, even sawdust. A gallon of water can be broken down into quarts, cups, even drops. But there comes a point where it can be broken down no longer and still retain it s basic properties. In other words, there is a point where water can get no smaller, and still be water.