With its cover removed this is a very early example of how electricity was measured on the consumer premises and thus accurately billed. Many of the first electric utility plants billed their customers depending upon the candelepower of the lightbulbs installed on their premises. As electrical appliances soon came upon the scene by 1900 the "flat-rate per lightbulb" method was abandoned on a widespead basis throughout the industry and electric meters like this one were installed to measure actual customer use.