Some 2,500 years ago, the ancient Greeks identified air — along with earth, fire and water — as one of the four elemental components of creation. But it made excellent sense at the time, and there was so little reason to dispute it that the idea persisted until the late 18th century.It might have endured even longer had it not been for a free-thinking English chemist and maverick theologian named Joseph Priestley.An Englishman by birth, Priestley was deeply involved in politics and religion, as well as science.
Some 2,500 years ago, the ancient Greeks identified air — along with earth, fire and water — as one of the four elemental components of creation. But it made excellent sense at the time, and there was so little reason to dispute it that the idea persisted until the late 18th century.Tags: Phd Thesis Earthquake Engineering12 College Admission Essays That WorkedPaper Industry Research ReportPersuasive Essay Topics College StudentsEssays Mother Daughter RelationshipsHomework Help CanadaHow To Write A Rationale For A Research PaperHow To Write An Essay For DummiesEssays And Reviews Summary
The steam engine was in the process of transforming civilization, and scientists of all types were fascinated with combustion and the role of air in it. In 1754, Joseph Black identified what he called "fixed air" (now known to be carbon dioxide) because it could be returned, or fixed, into the sort of solids from which it was produced.
In 1766, a wealthy eccentric named Henry Cavendish produced the highly flammable substance Lavoisier would name hydrogen, from the Greek words for "water maker." Finally in 1772, Daniel Rutherford found that when he burned material in a bell jar, then absorbed all the "fixed" air by soaking it up with a substance called potash, a gas remained.
Among them was the colorless and highly reactive gas he called "dephlogisticated air," to which the great French chemist Antoine Lavoisier would soon give the name "oxygen." It is hard to overstate the importance of Priestley's revelation.
Scientists now recognize 92 naturally occurring elements-including nitrogen and oxygen, the main components of air.
Before long, he was encouraged to study for the ministry.
And study, as it turned out, was something Joseph Priestley did very well.Young Joseph was sent to live with his aunt, Sarah Priestley Keighley, until the age of 19.She often entertained Presbyterian clergy at her home, and Joseph gradually came to prefer their doctrines to the grimmer Calvinism of his father.That he made a living through lectures and sermons is further evidence of his extraordinary nature.) In 1762, he was ordained and married Mary Wilkinson, the daughter of a prominent iron-works owner.She was, he noted, "of an excellent understanding, much improved by reading, of great fortitude and strength of mind, and of a temper in the highest degree affectionate and generous; feeling strongly for others and little for herself." Priestley traveled regularly to London, and became acquainted with numerous men of science and independent thought, including an ingenious American named Benjamin Franklin, who became a lifelong friend.Dedicated August 1, 1994, at the Joseph Priestley House in Northumberland, Pennsylvania, USA, and August 7, 2000, at Bowood House in Wiltshire, UK.Priestley House Commemorative Booklet (PDF) Bowood House Commemorative Booklet (PDF) Landmark Lesson Plan: When Joseph Priestley discovered oxygen in 1774, he answered age-old questions of why and how things burn.Back to top In 1767, Priestley was offered a ministry in Leeds, Englane, located near a brewery.This abundant and convenient source of "fixed air” — what we now know as carbon dioxide — from fermentation sparked his lifetime investigation into the chemistry of gases.They comprise 78 and 21 percent of the atmosphere, respectively.Back to top In the mid-18th century, the concept of an element was still evolving.