| The diamond jar is a cross between the spotted
tube and the Leiden jar.
The inner and outer coatings of the jar are made up of diamonds with small
spaces between their points. Holes punched in the coatings allow the sparks
that jump as the jar is charged to be seen clearly. The device is also called
a Spangled Jar.
The two diamond jars I have seen are at Oberlin College (at the left) and Otterbein College (at the right), both in Ohio. The jars are identical and unmarked.