No more than fifty dollars can be sent in one order, nor more than three orders to the same person in one day. The number of these offices is more than 1,400. The rates of commission on money orders are, On orders not exceeding $10 5 cents. Over $10, and not exceeding $20 10 cents. ” $20, ” ” $30 15 cents. ” $30, ” ” $40 20 cents. ” $40, ” ” $50 25 cents. No fractions of cents allowed in orders. When a money order has been lost or destroyed, a duplicate can be got, by the person who bought the order or by the person it was bought for, by applying either at the office where the order was bought or at the office where it should be paid. The Money Order Department is in charge of the Superintendent of the Money Order System. An international money order system, between the United States and Switzerland, went into operation September 1st, 1869, whereby the exchange of Postal orders between the two countries is effected through the agency of two Post Offices termed International Exchange Offices. The Office of New York City being set apart for the United States, and that of Basle, in Switzerland, for that country. The amount drawn for cannot exceed fifty dollars in one order, three orders only can be obtained by the same person in one day. The system works satisfactorily, and will no doubt be extended to Great Britain, and perhaps other European Nations at an early day. THE OFFICE OF FOREIGN MAILS. It has the care of all foreign postal arrangements and the supervision of the ocean mail service. It is presided over by a Superintendent. THE AUDITOR OF THE TREASURY FOR THE POST OFFICE DEPARTMENT. This is a bureau of the Treasury Department, which, for convenience, is located in the General Post Office. To this officer is assigned the duty of auditing the accounts of the Post Office Department, all communications relating to the accounts of postmasters, mail contractors, and other agents of the Department, are addressed to this officer. The head of so large and important a department of the public service is properly a chief officer of the government and has a seat in the cabinet. NUMBER OF POST OFFICES AND MILES OF POST ROADS IN THE U. S. In 1790 there were but 75 post offices, and 1,875 m. of post-roads. 1800 ” 903 ” 20,817 ” 1810 ” 2,300 ” 36,400 ” 1820 ” 4,500 ” 72,492 ” 1830 ” 8,450 ” 115,176 ” 1840 ” 13,463 ” 155,739 ” 1850 ” 18,417 ” 178,672 ” 1860 ” 28,498 ” 240,594 ” 1870 ” 28,492 ” 231,232 ” POSTMASTERS GENERAL.