Discovery of Oxygen

I am fortunate to live in the West Country of England – surrounded by places of history and great discoveries! Not far, in a town called Calne, is a house where the element Oxygen was first isolated. Any scientist will tell you, research takes money – lots of it! So it seems to study the discovery of oxygen, one must begin by following the money trail. That starts with the son of a clothier, William Petty. Sir William Petty Petty’s resume is quite remarkable for a lad of such humble beginnings. Vast fortunes were made during the 17th century and Sir William Petty, who lived from 1623-1687, found a way to step up from his first job as a cabin boy to a wealthy man by the age of thirty-five. Sir Petty knew the value of education and took every opportunity to obtain it. He studied anatomy, became a professor at Oxford University in 1651, and advanced to Physician General for Cromwell’s army in Ireland. While there, he directed the first complete survey of that country and was rewarded with 30,000 acres in Southwest Ireland plus a handsome bonus (for that time) of £9,000. Petty was a founding member of The Royal Society, the premier scientific organization in Great Britain and until his death; he was a respected expert in the field of political mathematics – what we call today, economics. Though Sir William had two sons, neither produced a male heir. According to protocol, upon Sir William’s death the family’s great wealth was passed on to his daughter’s son and until he was of age, to his daughter’s husband, Thomas Fitzmaurice.  Thomas inherited not only Sir William’s fortune, but through his wife, also gained the title of 1st Earl of Shelburne and the name of Petty. Lord Shelburne (Thomas Petty Fitzmaurice) bought Bowood House near Calne in Wiltshire, England in 1754 and set about on a long-term renovation project of the house and extensive gardens. Thomas’s son William (1737-1805), the 2nd Earl of Shelburne, continued his father’s efforts to turn Bowood into a showcase William Petty, 2nd Earl of Shelburne, built a ... estate. As a patron of the arts, he frequently opened Bowood for entertaining the “A” list in the worlds of literature, science, arts, and politics.
Portrait of Joseph Priestley

Portrait of Joseph Priestley (Photo credit: Wikipedia)

Joseph Priestley was a clergyman of many talents – including several branches of science. The wages of a clergyman were not sufficient to dabble in serious scientific studies. At the encouragement of friends like Benjamin Franklin, Priestley accepted a more lucrative position at Bowood where he would direct the education of Lord Shelburne’s children and act as his assistant. It was a job that afforded Priestley time, and most importantly, money to work on testing his scientific ideas. Joseph Priestley wanted to support the Phlogiston Theory that stated all combustible substances contained a material called phlogiston. While at Bowood, he isolated an “air” by concentrating sunlight on a glass tube of mercuric oxide. Satisfied that the special “air” did not harm the mice on which he tested, he tried it on himself! In hindsight, we now know this was an extremely dangerous act and certainly would be a major breech in today’s safer laboratory practice!! Along with the oxygen, it is possible that Joseph Priestley inhaled toxic mercury fumes, the effects of which would not be immediately apparent. Priestley described the effects of the isolated “air” as being many times more powerful than atmospheric air and named it dephlogisticated air. He inferred its properties supported the Phlogistic Theory because when a burning substance was placed in a closed container, combustion stopped. The phlogiston within the substance simply depleted and the special air that Priestley observed was a byproduct of that depletion (thus the prefix “de” meaning to remove or reduce). Priestley also observed that candles glowed brighter in the presence of the dephlogistiated air. He believed this also supported the Phlogistic Theory since the air given off by the process of combustion was now free to combine with phlogiston in other substances, like the candle. There is little doubt that Priestley’s best science was conducted at Bowood House. While touring Paris with Lord Shelburne in 1774, Priestley met French chemist Antoine Lavosier to discuss combustion. Priestley demonstrated his mercury oxide experiment. Later, Lavosier repeated Priestley’s experiment and did a few of his own. Using the quantitative data from the works of other scientists like Joseph Black and Henry Cavendish, Lavosier wrote several papers to explain the process of combustion. "A Word of Comfort" by William Dent ... After Priestley returned to England, his focus switched from science to religion, politics, and philosophy. He wrote several articles and pamphlets regarding his extreme and liberal ideas. Nearly seven years after moving into Bowood House, Priestley and Lord Shelburne had a falling-out. Some people say it was because Priestley’s controversial ideas were not good for Shelburne’s political career, others say there was a rift between the out-spoken philosopher and Shelburne’s new wife. Priestley left Bowood House to resume his clerical career. His church became a bully pulpit from which he preached contentious views until, in 1791, an angry mob burned his house and church. Fleeing to London, Priestley remained controversial by openly supporting the French Revolution – the revolt that cost Lavosier his head on the guillotine! The persecutions mounted until Priestley and his family emigrated to America in 1796. He lived another ten years in his house (and laboratory) along the banks of Pennsylvania’s Susquehanna River.
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