Benjamin Franklin, Environmentalist
Franklin, Joseph Priestley, and the Discovery of Ecosystems
Jul 31, 2009
Well before the coming of the American Revolution, Benjamin Franklin enjoyed a worldwide reputation as a scientist. His experiments with electricity, and his resulting invention of the lightning rod, were his best-known achievements; but he also devised bifocal glasses, the Franklin stove, a unique musical instrument called a glass armonica, and many other devices which added significantly to human safety, comfort, and enjoyment. Yet one of his greatest contributions to science remains little known, even though it has become of immense importance in recent years.
Franklin’s Friendship with Joseph Priestley
In London in 1765, Franklin was introduced to Joseph Priestley, a young clergyman, educator, political theorist, and philosopher, whose later achievements would include the discovery of oxygen, the invention of soda water, and the co-founding of the Unitarian Church in England. Priestley hoped to write a history of the scientific study of electricity, and sought out Franklin as one of the leading authorities on the subject. The two men began a friendship and an exchange of ideas that would continue until Franklin’s death in 1790.
Priestley’s Experiments with Spiders, Plants, and Air
After Priestley’s book on electricity was published, the young scientist turned his attention to chemistry in an attempt to determine the nature of air. Although everyone knew that all breathing creatures required air to live, it was not yet understood that air was a mixture of gases. Priestley, observing that a spider placed in a sealed jar would soon die, asked himself: if the spider died because it used up all the air, then what was left in the jar? Further experiments showed that a plant in a sealed jar did not die, and that when a spider was added to a jar containing a plant, it lived significantly longer than a spider that was in a jar without a plant. Priestley concluded that there was a substance in air that supported animal life; and that this substance was used up by the spiders, but replenished by the plants. This substance was, of course, what we now call oxygen.
Franklin and the Meaning of Priestley’s Discovery
Joseph Priestley is often summed up in histories of science as “the discoverer of oxygen” – a significant achievement, to be sure. But what Priestley really discovered was something much more momentous. He discovered that air was not a fixed part of the natural world like light or gravity, something that had always been there and always would be. Rather, air was something that was created, at least in part, by the activity of living organisms. Franklin immediately saw the implication of Priestley’s discovery: if an essential part of the natural world, the air we breathe, is itself a product of living things, then living things, including humans and their activities, can and must affect the natural world.
The Beginnings of Environmentalism
It was widely believed in the 18th century that trees and other plants should not be allowed to grow too close to a dwelling, not only because they would restrict the circulation of air, but also because plants themselves were thought to emit toxic vapors detrimental to people. Franklin, relying on the insights provided by Priestley’s experiments, insisted that this was nonsense; and he voiced the hope that the new scientific understanding of plants and their relation to the air we breathe would put an end to the practice of destroying trees that grew too near houses. Franklin and Priestley were ahead of their time. But their first glimpses of what we now call ecosystems eventually led to the development of environmental sciences and to an increasing understanding of human activity’s effects on the world we live in.
Source:
Johnson, Steven. “Green Ben: 250 years ago, Benjamin Franklin started thinking a lot like Al Gore. No one listened to him either.” American History 44(3):26–33 (August 2009).
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