Michigan State's campus was among the first to serve as a botanical laboratory for its faculty and students and is the site of what is, today, the oldest continuously operated botanical garden in the US.[5] In December 1879, Professor William J. Beal buried seeds of 23 common plants in 20 jars of sand (to prevent water accumulation) in various locations around campus. At certain fixed intervals, currently every 20 years, a jar is dug up to determine which seeds still germinate after their prolonged periods of unlit isolation.