Secret Materials and Chymical Exotica, or, How to Make the Luminescent Bologna Stone

Time: 6:00 p.m.

Location: Fayerweather 411, 1180 Amsterdam Avenue, Columbia University, New York, NY

Speaker: Larry Principe, Departments of Chemistry and History of Science, Johns Hopkins University

Two major features of 17th-century chymistry, secrecy and material production, come together in "chymical exotica"--highly sought-after materials with strange properties. Several such curiosities and secrets of their preparation became objects of exchange and of credit among 17th-century chymists. One of the most famous of such materials was the Bologna Stone, the first artificial phosphor, invented by an Italian cobbler in 1602. Oddly, although the method of preparing it was published several times, by the 1650s it was widely considered a lost secret because no one could get the procedures to work. Only in the 1680s did a young chymist named Wilhelm Homberg manage to recover it. Modern replication using Homberg's unpublished notes, method, and rebuilt apparatus reveals much about both the process and the original experimenters, and showcases the unexpected problems and the enormous potential of replicating historical processes. It also leaves a few secrets yet to be uncovered.