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    This is a detail of a Puck cartoon drawn in 1896 by Frederick Burr Opper. It depicts Uncle Sam participating in the blue glass craze described in this audio clip. (Library of Congress)

    Is blue-tinted glass good for your health? Augustus James Pleasonton, a general in the American Civil War, certainly believed so. In 1876 he  published The Influence of the Blue Ray of the Sunlight and of the Blue Color of the Sky.

    In this audio clip, Doug Mooney, senior archaeologist at URS Corporation and president of the Philadelphia Archaeological Forum, describes how his team dug up a pipe bowl during an archaeological survey of I-95 in Philadelphia. The pipe bowl was completely ordinary except for the words “blue glass” on its side.

    Doug’s team discovered that the pipe bowl was manufactured during a craze for blue glass sparked by Pleasonton’s book (which was printed in blue ink). Pleasonton believed that light filtered through blue glass would help plants grow. Why, you might ask?  Because the sky is bluer in the summer than in the winter. Plants grow faster in the summer, ergo blue light is responsible (at least according to Pleasonton). Eventually he extended his theory to the point where blue light could heal sick animals and humans. Many Americans replaced their windows with blue glass to improve their children’s health.

    By the time people realized Pleasonton was a quack,  a decade had passed and thousands of advertisements and branded pipe bowls had been manufactured, one of which ended up being found by Mooney’s archaeologists. Tune in to August’s Distillations podcast to learn more about Doug Mooney’s dig and urban archaeology in general.

    The Teeth Beneath Your Feet: The Urban Archaeology Podcast

    Where can you find a teacup, the molar of a goat, and an arrowhead all in one place? At an urban archaeology site, that’s where. This episode of Distillations goes underground, and reveals the fascinating worlds beneath our city shoes.

    “The Teeth Beneath Your Feet: Oddities in Urban Archaeology” features urban archaeologists Doug Mooney, senior archaeologist at URS corporation and president of the Philadelphia Archaeological Forum, and Deirdre Kelleher, who is finishing her doctorate at Temple University.

    We visit an artifact processing lab where volunteers are dusting off thousands of objects from a historic street in Philadelphia, and then we stop in on an excavation site alongside Interstate 95. Finally our guests discuss public archaeology, debunk a few of the field’s myths (no dinosaurs here, folks), describe the unique process of digging in cities, and explain why archaeology is important for everyone.

    Archaeology Exhibit

    The photographs above are from an archaeology exhibit at the First Presbyterian Church of Kensington on July 17. These artifacts were found by Doug Mooney’s Digging I-95 project. The latest episode of Distillations podcast goes into more depth about the project and urban archaeology.

    In a Philadelphia basement a family buried their pet dog and hamster with a doll’s head. More than 200 years later, archaeologists excavated the basement and found the curious burial ground. Why did the family bury their pets inside their home? What significance did the doll head have? No one knows, but a group of archaeologists working on the Digging I-95 project are studying a plethora of artifacts to learn about the lives of Philadelphians from the 1800s.

    Working for the URS Corporation and led by Doug Mooney, these archaeologists are excavating sections of I-95 to ensure that valuable history is not destroyed when construction on the freeway begins. So far they have found many informative (and strange) things left behind by 19th-century Philadelphians. On July 17 I went to an exhibition at the First Presbyterian Church of Kensington to see what they dug up.

    Many of the objects on display were made of glass. The neighborhood being excavated was once inhabited largely by employees of Dyottsville Glassworks, a major glass factory in the 17th century. During breaks or after work, workers would use their glass-blowing skills to create personal projects  known as “whimsies.” Researchers have identified many of these objects in the I-95 site, including toys, glasses, and even lactation aids. The archaeologist presenting the glass lactation aid was not entirely sure how it was used. “It looks extremely uncomfortable,” a spectator commented.

    Another archaeologist was using UV light to show what elements a drinking glass was made from. One of the glasses glowed yellowish-green under the light, indicating that it contained uranium. “Don’t worry,” the archaeologist assured onlookers. “There is not enough uranium to harm you. Unless you were to grind up the glass and eat it.” Uranium and other elements were used to add color to glass before the danger of radiation was fully understood.

    At another table, an archaeologist explained how they recreated cologne recipes by cross-referencing labels on the empty bottles they found with the ingredients listed in historical books and magazines. According to The Virginia Housewife, making Hungarian Water requires “one pint spirits of wine, one ounce oil of rosemary, two drachms essence of ambergris.” It smells sort of like incense.

    We’ll be talking to Doug Mooney and Deidre Kelleher (an archaeologist doing work at Philadelphia’s Elfreth’s Alley, which is right down the road from CHF) in August’s Distillations podcast about archaeology and chemistry. To listen to previous episodes of Distillations, look for it on iTunes or go to CHF’s website.

    By Jacob Roberts

     Most people associate earthworms with nutrient-rich soil, healthy gardens, and compost piles. It turns out these creatures, which can be so helpful to backyard gardeners, may be harming North American forests.

    Researchers suspect that the last ice age wiped out the vast majority of earthworm species in North America; almost no native earthworms can be found living in parts of the continent once covered by glaciers. European settlers reintroduced earthworms to regions that had developed worm-free ecosystems for thousands of years. Many of the worms likely hitched a ride in the soil used for ship ballast and in potted plants Europeans brought to farm in the New World. Other settlers intentionally brought worms to help vegetable gardens grow. Burrowing by worms lets air and water penetrate dense soil, and the worms break down nutrients so that some plants can absorb them more easily.

    But hardwood forests are very different from gardens and farms. Before earthworms showed up, fallen leaves decayed slowly on the forest floor, creating a thick layer of organic matter (called the “duff” layer) that allowed many species of ferns, flowers, and saplings to grow. After worms have invaded a forest, they mix the duff layer into the soil and break down organic material much more quickly. Native plants and flowers can have a hard time adapting to this change and usually just die off, often supplanted by other invasive species, such as buckthorn. It’s easy to tell the difference between a worm-free forest and a wormy forest: the former has a thick layer of small ferns and shrubs, and the latter has nearly bare, hard packed soil.

    Earthworms also change the chemical consistency of soil. A faster decomposition cycle in a forest’s soil allows active bacteria to release more CO2 into the atmosphere, and worms increase the overall pH of the soil making it harder for native species of plants and insects to survive. They also add potassium and phosphorous, which benefit some plants (especially crops) but not trees.

    Northern states have begun asking people to be mindful of what they dump in forests to avoid the spread of earthworms. Fishermen in particular are cautioned not to release unused worms into the soil. Next time you dig up a plant in your vegetable garden and grasp a handful of black, wormy soil, remember that those tiny burrowers are also foreign invaders.

    For more about early-American soil chemistry, check out this magazine article.

    By Jacob Roberts

    Image: A 1998 chemistry set for testing soil quality in CHF’s collections. Photograph by Gregory Tobias.


    Happy Birthday OXYGEN.  I guess.  Words enter language and sometimes words disappear-often as quickly as they appeared.  In the transition from the ancient ideas of the ‘four elements’ of earth, air, fire and water, to the modern Periodic table, scientists struggled to understand basic chemical reactions such as oxidation.  In 1730 the word phlogiston entered the scientific vocabulary, meaning a hypothetical inflammatory principle, formerly believed to exist in all combustible matter, and later extended to cover reactions such as oxidation.  The word came into English from Modern Latin around 1702, which came from the Ancient Greek word φλογιστον phlogiston (1610s in this sense), neuter of φλογιστος phlogistos meaning burnt up, inflammable, from φλογιζειν phlogizeinto set on fire, burn, which came from from φλοχ phlox (genitive phlogosflame, blaze.  The theory was propounded by German chemist George Ernst Stahl in 1702, denied by French chemist Antoine Lavoisier by 1775, defended by English theologian and chemist Joseph Priestley but generally abandoned by 1800. When Lavoisier composed the word oxygen in 1777 (in French, oxygen entered English in 1790), he was reacting to and rejecting the idea of phlogiston, composing his word from the Ancient Greek word oxys meaning sharp or acid and the -gene suffix used to indicate the origin orformation of something.  The word was meant to indicate‘acidifying principle’ because it was considered essential in the formation of acids, though this has since been shown not to be true. In fact, when Priestley isolated oxygen for the first time on August 1, 1774 he called it deplhogisticated air, but Lavoisier’s endeavors a year later meant the end of the phlogiston.

    Image of iron oxidation courtesy Dustin Jamison, used with permission under a Creative Commons 3.0 License.

    Oxygen has a fascinating history. Check out Joseph Priestley’s biography page on the Chemical Heritage Foundation’s website and an article about James Woodhouse from our magazine.

    Coffee and Quinine


    Historian Jon Grinspan wrote in the New York Times recently that during the American Civil War Southerners desperately roasted and brewed everything from potatoes to acorns in hope of simulating coffee. Even if coffee couldn’t cure disease, it may have been valued above any medicine by soldiers on both sides of the war. According to Grinspan, troops gushed about coffee in their diaries and letters, some going so far as to cite it as the reason they were still alive.

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    Monsters of the Pleistocene


    Sloths the size of elephants. Fish with menacing fangs. A rhinoceros with a horn so comically large that some believe it inspired the first unicorn stories.  In short, ice age animals were weird. These creatures lived during the Pleistocene era, roughly 2.6 million to 11,700 years ago, a period during  which the Earth went through multiple ice ages. Despite the harsh climate the megafauna thrived. Some looked like oversized versions of animals living today, while others were just plain awesome. Here I introduce you to a handful of Pleistocene megafauna that you might be glad are extinct. When you’re finished, check into the possibility of cloning woolly mammoths, another resident of the Pleistocene, in the latest issue of our magazine.

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    Arnold Thackray Turns 75: Celebrate with Some Atoms of History

    In this video on John Dalton’s atomic theory, a gentleman-historian tells the story of a scientific discovery of first rank: how Dalton, a teacher in Manchester, England, in the early 19th century single-handedly revived the ancient concept of atoms and gave it an experimental foundation. It is nothing less than the foundation of modern chemistry, explained in just six minutes. The storyteller is obviously at ease with both the camera and the books around him, and the viewer is immediately captured by the story, and even more so by the man explaining it. Who is this man?

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