Gassiot's Shower
 In the late 1970's I visited Oberlin College and discovered the tinfoil-lined goblet at the left. It was a little larger than one would expect for a goblet (20 cm) and its stem was yellow, "vaseline" glass, which uses uranium salts as the coloring agent. It did not appear to be a Leiden jar with its outer conducting foil missing, and I was mystified. 

   Eventually a copy of John Henry Pepper's 1866 book, A Boy's Play-Book of Science, was added to my collection, and I discovered the illustration below. 
   What I had seen was a a cup from Gassiot's Cascade or Shower. The Englishman John Peter Gassiot (1797-1877) invented what we now call discharge or Geissler tubes in 1852. Gassiot's Shower is simple a discharge tube on a large scale and was first described in 1854. The tinfoil-lined goblet was placed on the metallic base plate of a vacuum pump, with an electrical connection made to the tinfoil covering through a brass rod sliding through a vacuum seal at the top of the bell jar. The terminals of an induction coil were connected to the pump plate and the top of the brass rod, and the discharge took place between the foil and the pump plate. Blue streamers ran from the inside of the goblet to the pump plate, looking like a fluid spilling out of the goblet.
   Nearly twenty years later I discovered another tinfoil-lined goblet in the Millington/Barnard Collection in the University Museum at the University of Mississippi. 

   This is much larger than the Oberlin example.
 

REF: Thomas B. Greenslade, Jr., "Nineteenth Century Textbook Illustrations XXXV/Gassiot's Cascade", Phys. Teach., 18, 296-297 (1980)
 








   Still later I discovered a bell jar with the sliding rod used to make contact with the inisde of the goblet. This appartus is at Case Western Reserve University in Cleveland.



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