Carriers must know their districts, understand regulations covering the delivery of mail, handling of registry, insurance and collection on delivery matter, collection of mail and handling of change of address and forwarding orders. The inspector, however, determines when conditions are such at an office that city delivery service may be installed, the number of carriers necessary, and the number of deliveries to be made. He lays out the routes, locates the collection boxes, and fixes the schedules. He is also called on to investigate the service when extensions are desired or when carriers are deemed necessary, and is concerned with clerks, supervisory officers, postmasters, new post-offices, railway mail service, contracts for transportation of mail and furnishing of supplies, as well as the enforcement of criminal statutes covering train robberies, post-office burglaries, money-order forgeries, lottery men, the transmission of obscene literature, mail-bag thieves, embezzlers, etc. [Illustration] The following regular employees were in the Post-office Department and Postal Service on July 1, 1922: Post-office Department proper 1,917 Post-office inspectors 485 Clerks at headquarters, post-office inspectors 115 Employees at United States Envelope Agency 10 First Assistant Postmasters: First class 834 Second class 2,808 Third class 10,407 Fourth class 37,899 ------ 51,948 Assistant postmasters 2,730 Clerks, first and second class offices 56,003 City letter carriers 39,480 Village carriers 1,111 Watchmen, messengers, laborers, printers, etc., in post offices 3,063 Substitute clerks, first and second class offices 11,283 Substitute letter carriers 10,765 Special delivery messengers (estimated) 3,500 Second Assistant: Officers in Railway Mail Service 149 Railway postal clerks 19,659 Substitute railway postal clerks 2,419 Air mail employees 345 Fourth Assistant: Rural carriers 44,086 Motor-vehicle employees 3,177 Substitute motor-vehicle employees 447 Government-operated star-route employees 64 -------- Total 252,756