Stia meter for direct current ampere-hours

The meter presented here is a device used for measuring direct current ampere-hours consumed by a customer. The apparatus is based on a concept developed by Thomas Edison, who used a phenomenon involving the flow of a material with electrostatic properties between electrodes to measure current. The STIA meter is based on a technology patented by Max Gossman in 1922 and uses the hazardous metal mercury. Current flowing through a container of mercury makes it move along a capillary. For a direct current with a fixed voltage, the amount of metal filling the capillary is proportional to the number of ampere-hours consumed by the customer. The design of the device incorporates a base for the counter that is fixed to the dashboard and, mounted on it with a hinge and tilting upwards, a container with a capillary vessel and scale used for reading the meter. Manufacturer: Schott & Genossen Jena, 1920s-1930s Inv. No.: MIM1915/IV-126 Model prepared on the basis of photogrammetric measurements. Licence: CC BY-NC-SA