George Washington was a microbiologist

True story.  I am completely not making this up.

George Washington, commander of the revolutionary army and the first President of the United States, performed some of the earliest documented experiments in microbiology, when he and a team of collaborators, including Thomas Paine, paddled out into the Millstone River in central New Jersey to perform an experiment.  Paine, who wrote Common Sense, went to see General Washington with a letter of introduction from Ben Franklin who had hoped to secure a pension from the US Congress for Mr. Paine.  For inspiration, Washington had selections from Paine's writings read aloud to his troops each night in the hopes that it would inspire them during the war.  At any rate, Paine had heard that there were sections of the river that could be set on fire so, one night, he, Washington and some troops paddled out into the river. As Paine wrote of the incident in a letter on November 5th of 1783:

We had several times been told that the [Millstone] river… might be set on fire… When the mud at the bottom was disturbed by poles, the air bubbles rose fast, and I saw the fire take from General Washington’s light and descend to the surface of the water... This was demonstrative evidence that what was called setting the river on fire was setting on fire the inflammable air that arose out of the mud.

But Washington wasn't alone in these early experiments.  At approximately the same time, Allesandro Volta, the Italian scientist for whom the term volt is named, wrote to Father Carlo Campi in November 1776 (7 years before the Washington-Paine experiment) of conducting similar experiments on Lake Maggiore in the Italian Alps:

So, on the 3rd of this month, with my head full of such ideas, and being in a little boat on Lake Maggiore, and passing close to an area covered with reeds, I started to poke and stir the bottom with my cane.  So much air emerged that I decided to collect a quantity in a large glass container… This air burns with a beautiful blue flame.

The “flammable gas” referred to in these experiments was “swamp gas,” of which a large component is methane, a little molecule in which one carbon is bonded to four hydrogens.  Chemical formula: CH₄.

You may wonder where the "microbiology" comes in.  Here's how:

There are a group of microscopic organisms that derive chemical energy from the conversion of carbon in a variety of sources into methane.  These methanogens (“methane making”) are not classified as bacteria but, rather, come from a separate kingdom, Archaea, which derives from the Greek word 'arcaia' which means “ancient things” (archaic has the same root). Typically, methanogens live in mud on the bottoms of relatively quiet rivers and ponds.  You don’t have to do anything to get them to grow except create conditions in which they can flourish.  Typically that means (a) remove the oxygen (these environments are called “anoxic”) and (b) provide a nice source of carbon, usually in the form of decaying organic matter (tree leaves, for instance).  Other natural sources include carbon dioxide, methanol, acetic acid (among others), and halocarbons (there is some evidence that methanogens can help to detoxify chemical wastes, so this chemistry has implications beyond historical interest).

Did Paine know about Volta's experiments?  Seems unlikely, but it’s interesting to note that, over a century before quantum mechanics, citizen-farmer-statesmen-scientists were studying the natural world to understand the how and why.  They may not have known about atoms, molecules, or the scientific method as practiced in the 21st century but, like any good scientist, they each designed an experiment that tested a hypothesis, collected their data, and analyzed their results.

Incidentally, methane is produced in landfills, by termites, and the rumens of cows – all regions where methanogens are allowed to flourish – and it is produced in enormous quantities.  Some estimates suggest that a billion tons of methane are released into the atmosphere annually where some of it is oxidized back to carbon dioxide and absorbed during plant metabolism, but it’s influence doesn’t stop there.  Methane is an important greenhouse gas.  It isn’t present to as great an extent as CO₂, but it has a higher heat capacity than carbon dioxide.