I connected a GTL-3 light bulb (which uses mercury vapor and emits the 253.7 nm spectral line) to two 9V batteries, covered it with an aluminum surface, and connected that surface through an ammeter to the ground of a wall outletThe bulb lights; however, I do not read any photoelectric current from the aluminum surface, even with the ammeter set to the microamp rangeI tried scrubbing the inside of the aluminum surface with a Scotch-Brite scrub sponge, but there is still no currentWhat could be the problem?Since your foil is on the outside of the glass bulb, possibly you need an ac nano-ampmeter, but I\'m unsure that would prove anything as you have at least two places in your series output circuit that are near infinite ohms dcElectrically conducting glass is possible, but the GT-3 bulb likely does not have electrically conducting glass.Other related question