Passage FourAt the 1893 Columbian Exposition, a World Fair held in Chicago, chocolate-making machinery made in Germany was displayed. It caught the eye of M.S. Hershey, who saw the potential for chocolate. He installed chocolate machinery in his factory in Lancaster, and produced his first chocolate bars in 1894.Other Americans began mixing in other materials to make up new candy bars throughout the end of the 1890's and the early 1900's. But it was World War Ⅰ that really brought attention to the candy bar.The U.S. Army Quartermaster Corps requested various American chocolate manufacturers to provide 20 to 40 pound blocks of chocolate to be shipped to quartermaster bases. The blocks were cut into smaller pieces and distributed to American soldiers in Europe. Eventually the task of making smaller pieces was turned back to the manufacturers. By the end of the war when the soldiers arrived home, the American candy bar business was assured. Why? Because the returning soldiers had grown fond of chocolate candy and wanted more of the same. As a result, from that time on and through the 1920's, candy bar manufacturers became established throughout the United States, and as many as 40,000 different candy bars appeared on the scene.The original candy bar industry had its start on the eastern coast in such cities as Philadelphia, Boston, and New York. The industry soon spread to the Midwest because shipping and raw materials such as sugar, corn syrup, and milk were easily available. Chicago became the seat of the candy bar industry and is even today an important base.Which event brought the booming of American candy bar business?