All mailable matter for transmission by the United States mails within the United States is divided into four classes, under the following regulations. (Domestic rates apply to Canada, Mexico, Cuba, Tutuila, Porto Rico, Guam, Hawaii, the Philippines, and certain places in China served through the United States postal agency at Shanghai.)

First-Class Matter

This class includes letters, postal cards, "post cards," and anything sealed or otherwise closed against inspection, or anything containing writing not allowed as an accompaniment to printed matter under class three.

Rates of letter postage to any part of the United States, two cents per ounce or fraction thereof.

Rates on local or drop letters at free delivery offices, two cents per ounce or fraction thereof.

Rates on postal cards, one cent (double or "reply" cards, two cents). Nothing must be added or attached to a postal card, except that a printed address slipknot larger than 2 inches by 3/4 of an inch may be pasted on the address or message side. The addition of anything else subjects the card to letter postage. A card containing any threat, offensive dun, or any scurrilous or indecent communication will not be forwarded. Words on a postal card indicating the occupation of the addressee, used to better identify him, are regarded as a part of the address; anything more as the repetition of the words on a postal card, etc., business or the several capacities in which the addressee serves, the various kinds of goods dealt in, and similar attempts at advertising on the address side of the postal card is not regarded as a "proper description of the person," and will subject the postal card to the letter rate. Cards that have been spoiled in printing or otherwise will be redeemed from the original purchasers at 75 per cent of their face value, if unmutilated.

"Private Mailing Cards," "Post Cards," bearing written messages may be transmitted in the domestic mails at the rate of a cent apiece, stamps to be affixed by the sender; such cards to be sent openly in the mails.

Rates on specially delivered letters, ten cents on each letter in addition to the regular postage. This entitles the letter to immediate delivery by special messenger. Special delivery stamps are sold at postoffices, and must be affixed to such letters. An ordinary ten-cent stamp affixed to a letter will not entitle it to special delivery. The delivery, at carrier offices, extends to the limits of the carrier routes. At non-carrier offices it extends to one mile from the postoffice. Postmasters are not obliged to deliver beyond these limits, and letters addressed to places beyond must await delivery in the usual way, notwithstanding the special delivery stamp.

Prepayment by stamps invariably required. Postage on all letters should be fully prepaid, but if prepaid one full rate and no more they will be forwarded, and the amount of deficient postage collected on delivery; if wholy unpaid, or prepaid with less than one full rate and deposited at a postoffice, the addressee will be notified to remit postage; and if he fails to do so, they will be sent to the dead letter office; but they will be returned to the sender if he is located at the place of mailing, and if his address be printed or written upon them.

Letter rates are charged on all productions by the typewriter or manifold process, and on all printed imitations of typewriting or manuscript, unless such reproductions are presented at postoffice windows in the minimum number of twenty identical copies separately addressed.

Letters (but no other class of mail matter) will be returned to the sender free, if a request to that effect is printed or written on the envelope. There is no limit of wight for first-class matter fully prepaid.

Prepaid letters will be reforwarded from one post-office to another upon the written request of the person addressed, without additional charge for postage. The direction on forwarded letters may be changed as many times as may be necessary to reach the person addressed.

Second-Class Matter

This class includes all newspapers and periodicals exclusively in print that have been "Entered as second-class matter" and are regularly issued at stated intervals as frequently as four times a year, from a known office of publication or news agency, to actual subscribers or news agents, and transient newspapers and publications of this class mailed by persons other than publishers. Publications having the characteristics of books and such as are not subscribed for on account of their literary merits, but because of other inducements, are not eligible to second-class privileges. Also periodical publications of benevolent and fraternal societies, organized under the lodge system and having a membership of a thousand persons, and of the bulletins and proceedings of strictly professional, literary, historical, and scientific associations and institutions, trade unions, etc., provided only that these be published at stated intervals not less than four times a year, and that they be printed on and be bound in paper. Publishers who wish to avail themselves of the privileges of the act are required to make formal application to the department through the postmaster at the place of publication, producing satisfactory evidence that the organizations represented come within the purview of the law, and that the object of the publications is to further the objects and purposes of the organizations.

Rates of postage to publishers, one cent a pound or fractional part thereof, prepaid in currency. Publications designed primarily for advertising or free circulation, or not having a legitimate list of subscribers, are excluded from the pound rate, and pay third-class rates.

Second-class publications must possess legitimate subscription lists approximating 50 per cent of the number of copies regularly issued and circulated by mail or otherwise. Unless they do pound-rate privileges are revoked or withheld.