As agricultural and wine interests developed north of the city limits, much of the light industry, banking, commercial and retail activity in the county evolved within the city of Napa and in earlier times along the Napa River through the historic downtown. Napa Glove Factory was established in 1903 and was the largest plant of its kind west of Chicago. The owners, Raymond brothers, went to Gloversville, New York. They wore sandwich boards to recruit the relocation of immigrant southern Italian workers. The surnames Greco and Lui are some of the many Napa families that followed this chain migration to work at factory jobs in the town, not to own land for farming. Edwin Pridham and Peter L. Jensen invented the moving-coil loudspeaker in 1915 in their Napa workshop while working on an improvement for the telephone receiver. Pridham and Jensen went on to found the Magnavox Company in 1917. In the late 19th century and early 20th century Napa was known for having the largest red-light district for a California city of its size. In 1905, Napa had brothels primarily concentrated on and around Clinton Street.