But the delivery of mail is only part of the story, for it is estimated that the public mail daily in the various chutes, classified station "drops," and street letter boxes, etc., approximate 5,000,000 pieces of first-class mail and several million circulars, all of which have to be gathered together and put through the various processes of cancellation, sorting, etc., before the actual work of delivery or despatch begins. The tremendous magnitude of the business of the various stations is shown not only in the volume of mail received and delivered, but in the sale of stamps, the collection of postage on second-class matter, etc., constituting the receipts. The receipts at the City Hall Station, for instance, are greater than the receipts of any post-office in the United States except Chicago, Ill., Philadelphia, Pa., and Boston, Mass., as shown by the table below, giving figures for the fiscal year 1921. In the case of all the offices named, the figures include not only the main office but all the stations of the offices. In the case of the City Hall Station alone, the figures are for this unit exclusively, and no other point. RECEIPTS FOR FISCAL YEAR 1921 Chicago, Ill. $ 42,711,561 Philadelphia, Pa. 15,588,738 Boston, Mass. 11,597,061 City Hall Station 9,749,018 Saint Louis, Mo. 8,722,633 Kansas City, Mo. 6,490,018 Cleveland, Ohio 6,218,695 Detroit, Mich. 5,742,835 Brooklyn, N. Y. 5,695,037 San Francisco, Cal. 5,623,409 Pittsburgh, Pa. 5,298,504 Cincinnati, Ohio 4,663,323 Minneapolis, Minn. 4,606,689 Los Angeles, Cal. 4,580,969 Baltimore, Md. 4,323,525 Washington, D. C. 3,661,760 Buffalo, N. Y. 3,438,497 Milwaukee, Wis. 3,311,922 From these figures it will also be seen that the receipts of the City Hall Station are greater than the receipts of the entire city of Saint Louis, as great as the receipts of Cleveland, Ohio, and Buffalo, N. Y., combined, as great as the receipts of Detroit, Mich., and Washington, D. C., combined, as great as those of Brooklyn, N. Y., and Milwaukee, Wis., combined, or those of Cincinnati, Ohio, and Minneapolis, Minn., combined. The rapid increase in the volume of business at the City Hall Station is shown by the following figures of receipts: Calendar Year 1915 $ 6,587,228.98 1916 7,124,138.76 1917 7,544,849.70 1918 8,162,774.76 1919 9,188,449.66 1920 10,253,435.42 Increase in five years--55.65 per cent. City Hall is not the only station of great receipts, as the following statistics show: RECEIPTS FOR FISCAL YEAR 1921-2