Electrometer, probably English-made, consisting of a glass tube with brass fittings and two electrodes, of which the upper is adjustable. A glass capillary tube is attached to the side. This is a simplified version of Ebenezer Kinnersley's "electrical air thermometer," which he described to his friend Benjamin Franklin in 1761. Colored water was poured into the airtight cylinder. A spark jumping between the two electrodes heated the air, which expanded, pushing the water up the capillary tube. This gave a crude measure of the electrical charge. Provenance: Lorraine collections.