Candy bars were originally made from only cocoa powder and sugar. During the latter part of the nineteenth century, confectioners began to experiment with other ingredients. Swiss confectioner, Henry Nestle, added milk to his chocolate recipe to reduce the bitterness of the cocoa. Rodolphe Lindt, a Swiss confectioner and inventor, began adding cocoa butter as an ingredient in 1879. The addition of cocoa butter allowed the chocolate bar to keep its shape and melt in the mouth. In the United States, immigrants who arrived with candy-making skills drove the development of new candy bars. Milton S. Hershey, a Pennsylvania caramel maker, saw a German-manufactured chocolate-making machine at the 1893 Chicago World's Fair. He immediately ordered one for his Lancaster factory and produced the first American-made milk chocolate bar. In 1897, following the lead of Swiss companies, Cadbury introduced its own line of milk chocolate bars, with Cadbury Dairy Milk, produced in 1905, becoming the company's best selling bar in the UK.