Behold the humble test tube. If you think it’s the symbol of chemistry, you’d be wrong, argues William Jensen, a chemistry historian and professor emeritus at the University of Cincinnati Department of Chemistry.
“At best, it’s a co-symbol,” said Jensen, who has combed paintings and old chemistry texts in search of data to date the test tube and other apparatus used in chemistry labs.
If you think the test tube dates back to alchemy, wrong again, said Jensen, who has been able to trace the test tube back only to the first decade of the 19th century. Actually, you’d probably be thinking of spherical vessels with a long downward-pointing neck known as the retort, glass or copper vessels used in distillation. (The idiom “snappish retort” may refer to the vessel.)
Liquids are placed in the retort to be heated. The neck acts as a condenser, allowing the vapors to condense, flow along the neck and be collected underneath, according to Wikipedia. In the case of alchemy, you would actually be thinking instead of a retort. No self-respecting alchemist would’ve been without one.
Jensen said, “Virtually every modern-day artistic depiction of an alchemist will feature a retort as the centerpiece of the alchemist’s laboratory,” he said. “Perhaps no single piece of laboratory apparatus is more intimately associated in popular culture with the practice of chemistry than is the retort.”
A Snappy Retort
A retort is depicted on the Boy Scouts of America’s chemistry merit badge, said Jensen. Likewise, the insignia for the Chemical Corps of the United States Army incorporates retorts.
Retorts first appeared in the literature dealing with distillation sometime in the 14th or 15th century, he said in an article entitled “A Snappy Retort” in Notes from the Oesper Collections (Museum Notes, January/February 2013, 1-6).
Common laboratory apparatus, including flasks (think Walter White, the high school chemistry teacher turned meth kingpin), beaker (think the Muppets) and retorts (think Merlin) before the 19th century was flawed.
Jensen said that’s because it did not have a high melting point; was not resistant to being destroyed by water, alkalis and acids; was not colorless and transparent; and was not resistant to thermal and mechanical stress.
Jensen has traced the creation of the test tube to the beginning of the 19th century. He said test tubes were used to heat chemicals, which, based on the colors that were seen, allowed chemists to identify chemicals.
Here Comes the Pyrex
Throughout the century, innovations in glassmaking, such as making it thin with tough glass, made the modern test tube possible.
In 1915, Corning Glass introduced Pyrex, which was superior in withstanding mechanical shock, Jensen wrote in his Ask the Historian column entitled “The Origin of Pyrex” (J. Chem. Educ., 2006, 83, 692-693). Pyrex first was used in cookware, but soon was applied to lab glassware. Test tubes are hanging in there. Retorts have been in decline for more than a century.
“Ironically, despite its continued use as a symbol for the practice of chemistry, the retort had already begun to disappear from day-to-day laboratory practice by the early decades of the 20th century…”, he said.