In 1885, Adolph Müller, commercial representative for the "Spiecker & Co. Electric Company" in Cologne, travelled to Rosport to get further information on the reliable accumulator running in Rosport already for several years. After spending a few hours with Henri Tudor, Müller was convinced that he had seen with his own eyes an innovation which could be developed on a large scale. The two men agreed to wait until the large-scale street-lighting system in Echternach had been put in place. Once that had passed the test, Müller would begin to market, in Germany, accumulators made in Rosport.