Burning Glass

Description (Brief)
Joseph Priestley (1733–1804) used this burning glass in his Northumberland, Pennsylvania laboratory. Priestley, the noted chemist whose accomplishments include the discovery of oxygen, was born in England. He lived and worked in Birmingham for many years, but his views as a Dissenter and an advocate of the French Revolution incited an angry mob into burning down his house and laboratory. In 1794 he fled to America, eventually settling in Northumberland, near Philadelphia. His great-great-granddaughter, Frances Priestley, donated his surviving laboratory ware to the Smithsonian in 1883.
Priestley is perhaps best remembered for his discovery of oxygen, which he called “dephlogisticated” air. Using a burning glass of twelve inches in diameter and twenty inches in focal length, he focused a beam of sunlight onto a piece of mercuric oxide contained in a glass vessel. The lens’s heat ignited the sample, giving off pure oxygen gas.
Priestley’s original burning glass very likely met its demise in 1791, when a mob angered by his political and religious beliefs burned and looted his lab in Birmingham, England. Spurred by this outburst, Priestley decided to relocate to Pennsylvania, taking with him a “capital burning lens, sixteen inches in diameter” made for him by Mr. William Parker of 69 Fleet St., London. Mr. Parker and his son Samuel, both glassmakers, supplied Priestley with laboratory glassware free of charge, even after his move to the United States.
Priestley seems to have made much use of this single-lens his burning glass and others in his final years. Letters of the time reflect his pleasure at the Pennsylvania climate compared to that of England, alluding to the fact that its greater number of sunny days allowed for more experimentation with the burning glass. Indeed, a footnote in his memoir states, “Though Dr. Priestley’s sight was not much worse than before, during the last ten years of his life, it had been much injured by his experiments with the burning lens, of which he made much use in summer time.”
Years after Priestley’s death, the sixteen-inch lens eventually made its way to the Smithsonian Institution where it was, ironically, lost in an 1865 fire. Smithsonian curators commissioned this replica of his original double-lens glass in 1961 from craftsman Laurits Christian Eichner, for inclusion in a re-creation of Priestley’s 1790 chemistry laboratory in the Hall of Physical Sciences at the National Museum of History and Technology.
Sources:
Badash, Lawrence. “Joseph Priestley’s Apparatus for Pneumatic Chemistry.” Journal of the History of Medicine and Allied Sciences 19, no. 2 (1964): 139–55. doi:10.1093/jhmas/XIX.2.139.
National Museum of American History Accession File #13305
National Museum of American History Accession File #236089
Priestley, Joseph. Experiments and Observations on Different Kinds of Air. 2d ed. cor. ... London, 1775. http://hdl.handle.net/2027/nyp.33433079424671.
Priestley, Joseph, and John Towill Rutt. 1817. The Theological and Miscellaneous Works of Joseph Priestley I, no. 2. London: Printed by G. Smallfield. http://archive.org/details/theologicalmisce0102prie.
Location
Currently not on view
Object Name
double-lens burning glass
maker of original instrument
Parker, William
maker
Eichner, Laurits Christian
Physical Description
cherry wood (overall material)
glass (overall material)
Measurements
large glass: 8 1/2 in; 21.59 cm
overall: 25 in; 63.5 cm
small glass: 4 in; 10.16 cm
ID Number
CH*319022
catalog number
319022
accession number
236089
subject
Science & Mathematics
Science & Scientific Instruments
Chemistry
Joseph Priestley
See more items in
Medicine and Science: Chemistry
Joseph Priestley
Data Source
National Museum of American History, Kenneth E. Behring Center

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