Browse Items (3471 total)

A large electronic valve with glass casing, plastic base and 4 pins. Part of a massive collection of valves in a cardboard box.

box, wooden frame with glass front and back. Brass rod connects a gold leaf to a top touch disc. Copper leaf against one side connected to an external thumb nut contact. Silver foil lining.

1 electrically tapped coherer on stand. Coherer is reset by electrically operated tapper. Glass tube replaced after breakage, c. 1990.

Brass cylinder with rounded ends on glass stand on wooden base; small round wooden feet; one hole at top of each end of cylinder; with engraving

two brass discs the upper suspended by a movable rod above the lower, possible to move electrical charge to demonstrate capacitance. The upper disc is held by an insulated pillar and curved brass rod

NB: The 1823 inventory of Copland's collection lists some glass globe generators like this one, but the provenance of this generator is unknown. It is certainly of an 18th century design so Copland would have had one very similar at least. While it…

Elliptic bell with a handle. No clapper or evidence of one; most likely struck with a small hammer.