Letters and parcels received for 1916 amounted to 10,839,890. Of this number 3,677,194 pieces were delivered, 101,485 filed, 7,019,436 destroyed and 41,775 under treatment. Checks, drafts, money orders and other valuable papers of the face value of $2,303,119.56 were found in undelivered letters, practically all of which was restored to the owners. The net revenue from the sale of undeliverable articles of merchandise and currency found loose in the mails, etc., aggregated $53,665.69. Advertised letters returned from the Dead Letter Office now require the payment of 1 cent, the revenue of this for the past six months amounted to $11,000, making net revenue $64,665.69, or within $10,000 of the whole amount required to conduct the operations of the office. Formerly all dead matter came to Washington for examination and disposition. Now there are twelve large cities in the country geographically arranged, to which dead matter is sent in addition to what is received in Washington. This has made it possible to largely reduce the force in the Washington office. The establishment of the Dead Letter Office dates back to 1825. Mail Locks There are four kinds of locks used by the Department, in protecting the mails, the brass padlocks seen on letter and package boxes, the iron lock used on mail pouches, the inside letter box lock, and the registered lock used to protect the more valuable mail. The locks and keys are made by the Government in the equipment shops at Washington. Of the iron lock there are something like a million in use. These locks are made at a cost of 8½ cents each and weigh but 2-4/5 ounces, the lightest and best lock ever used for the purpose. Locks previously in use cost a great deal more to make and keep in repair and were much heavier. The study of economy in various forms during the past four years has made it possible to introduce many reforms in the manufacture of locks of which the above is a significant example. Steel is now largely used in all lock equipment on account of the high cost of brass. All equipment used in mail transportation is made by the Government. Mail locks and keys were formerly made by contract, but during the administration of Postmaster General Dickinson it was decided to do this work under Government supervision. Public policy, no less than economy dictated this course. While the manufacture of Government locks was surrounded with all possible safeguard and precaution there could be no absolute assurance that the mechanism would be kept secret, would be safe from imitation, so the Government, both for security to the mails and for economic reasons, decided to have the work done under its own direction. Mail Pouches and Sacks