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(Revised by the Post-Office Department for THE WORLD ALMANAC.)
DOMESTIC RATES OF POSTACE.
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 mail for Canada, Mexico, Cuba, Tutuila, Porto Rico, Guam, Hawaii, the Philippines, the "Canal Zone," the Republic of Panama, and Shanghai, China, also to officers or members of the crew of vessels of war of the United States, and officers and men of the United States Navy in the United States Naval Hospital, Yokohama, Japan.)
First-Class Matter-This class includes letters, postal cards, post cards," and anything sealed or otherwise closed against inspection, except as provided for under other classifications or anything containing writing not authorized on mail matter of other classifications.
First class or letter rate of postage to any part of the United States, its possessions, or the abovenamed countries, two cents per ounce or fraction thereof.
Rates on local or drop letters at free delivery offices, two cents per ounce or fraction thereof. At offices where there is no free delivery by carriers, and the addressee cannot be served by rural free delivery carriers, one cent per ounce or fraction thereof.
Rates on postal cards, one cent (double or "reply" cards, two cents). Postal cards issued by the Post-Office Department may bear written, printed, or other additions as follows:
(a) The face of the card may be divided by a vertical line placed approximately one-third of the distance from the left end of the card; the space to the left of the line to be used for a message, etc., but the space to the right for the address only.
(b) Addresses upon postal cards may be either written, printed, or affixed thereto, at the option of the sender.
(c) Very thin sheets of paper may be attached to the card on condition that they completely adhere thereto. Such sheets may bear both writing and printing.
(d) Advertisements, illustrations, or writing may appear on the back of the card and on the left third of the face.
2. The addition to a postal card of matter other than as above authorized will subject the card, when sent in the mails, to postage according to the character of the message-at the letter rate if wholly or partly in writing or the third-class rate if entirely in print. In either case the postage value of the stamp impressed upon the card will not be impaired.
Postal cards must be treated in all respects as sealed letters, except that those mailed for local delivery will be returned to the sender if undeliverable and the name and address of the sender appears thereon. Undeliverable "double" postal cards will be returned to the sender if known.
4. Postal cards bearing particles of glass, metal, mica, sand, tinsel or other similar substances, are unmailable, except when inclosed in tightly sealed envelopes with proper postage attached, or when treated in such manner as will prevent the objectionable substances from being rubbed off or injuring persons handling the mails.
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.
POST CARDS-(private mailing cards)-bearing written or printed messages are transmissible in the mails. Private mailing cards (" post cards '') in the domestic mails must conform to the following conditions: (a) A 'post card'' must be an unfolded piece of cardboard not exceeding approximately 3 9-16 by 59-16 inches, nor less than approximately 234 by 4 inches,
(b) It must in form and in the quality and weight of paper be substantially like the Government postal card. (e) It may be of any color not interfering with a legible address and postmark.
(d) It may or may not, at the option of the sender, bear near the top of the face the words "post card. (e) The face of the card may be divided by a vertical line; the left half to be used for a message, etc., but that to the right for the address only.
Very thin sheets of paper may be attached to the card, and then only on condition that they completely adhere thereto. Such sheets may bear both writing and printing. (7) Advertisements and illustrations may appear on the back of the card and on the left half of the face.
2. Cards, without cover, conforming to the foregoing conditions are transmissible in the domestic mails (including the possessions of the United States) and to Cuba, Canada, Mexico, the Republic of Panama, and Shanghai, China, at the postage rate of 1 cent each.
3. When post cards are prepared by printers and stationers for sale, it is desirable that they bear in the uper right hand corner of the face an oblong diagram containing the words Place postage stamp here," and at the bottom of the space to the right of the verticle dividing line, the words This space for the address.''
4. Cards which do not conform to the conditions prescribed by these regulations are, when sent in the mails, chargeable with postage according to the character of the message-at the letter rate, if wholly or partly in writing, or at the third-class rate, if entirely in print.
5. Cards bearing particles of glass, metal, mica, sand, tinsel, or other similar substances, are unmailable, except when inclosed in tightly sealed envelopes, or when treated in such manner as will prevent the objectionable substances from being rubbed off or injuring persons handling the mails. Rate on special delivery 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 post-offices, and must be affixed to such letters. Ordinary stamps to the value of ten cents in addition to the regular postage, affixed to a letter or other piece of mail will entitle it to special delivery if it is marked Special Delivery. The delivery, at carrier offices, extends to the limits of the carrier routes. At nou-carrier offices it extends to one mile from the post-office. 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 wholly unpaid, or prepaid with less than one full rate and deposited at a post-office, 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 rate is charged on typewriting and carbon or letter press copies thereof, and on all printed Imitations or reproductions of typewriting or manuscript obtained by mechanical process unless such reproductions are presented at post-office windows in the minimum number of twenty identical unsealed copies.
Letters and other matter prepaid at the letter rate-two cents an ounce or fraction thereof-(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 or wrapper. The limit of weight is four pounds, except for a single book. Prepaid letters and other matter prepaid at the letter rate will be forwarded 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. Nothing may be added to such letters except the forwarding address without subjecting them to new postage.
Second-Class Matter-This class includes all printed newspapers and periodicals that have beenEntered as second-class matter," under the act of March 3, 1879, and are regularly issued at stated intervals as frequently as four times a year, from a known office of pub.ication and mailed by the publishers or news agents to actual subscribers or as sample copies or to news agents for sale, and newspapers and publications of this class mailed by persons other than publishers. Also periodical publications entered under the act of August 24, 1912, of benevolent and fraternal societies, organized under the lodge system and having a membership of a thousand persons, and the publications of strictly professional, literary, historical and scientific societies, and incorporated institutions of learning, trade unions, etc., provided that these be published at stated intervals not less than four times a year, and that they be formed of printed paper sheets without board, cloth, leather or other substantial binding. 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, societies, and institutions 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 and news agents, one cent a pound or fractional part thereof, prepaid in currency. Publications designed primarily for advertising or free circulation, or circulation at a nominal rate, or not having a legitimate list of subscribers, are not entitled to the pound rate under the act of March 3, 1879.
Publications which have not been admitted to the second-class are third-class matter.
Publications sent to actual subscribers in the county where printed and published are free, unless mailed for delivery at a letter-carrier office.
hates of postage on second-class newspapers, magazines, or periodicals, mailed by others than the publishers or news agents, one cent for each four ounces or fraction thereof. It should be observed that the rate is one cent for each four ounces, not one cent for each paper contained in the same wrapper. This rate applies only when a complete copy is mailed. Parts of second-class publications or partial or incomplete copies are third-class matter. Second-class matter will be entitled to special delivery when special delivery stamps (or ten cents in ordinary stamps and the words "Special Delivery" placed on the wrapper) are affixed in addition to the regular postage.
Second-class matter must be so wrapped that it may be easily examined. The sender's name and address may be written in them or on the wrapper, also the words "sample copy" when sent as such, or "marked copy" when it contains a marked item or article. Typographical errors in the text may be corrected, but any other writing subjects the matter to letter postage.
Third-Class Matter-Mail matter of the third class includes printed books, pamphlets, engravings, circulars in print (or by the mimeograph, hectograph, electric-pen, or similar process when at least twenty identical copies are mailed at post-office windows at one time), and other matter wholly in print, proof sheets, corrected proof sheets, and manuscript copy accompanying
The rate on matter of this class is one cent for each two ounces or fraction thereof. Postage must be paid by stamps aflixed, unless 2,000 or more identical pieces are mailed under special permit when the postage at that rate may be paid in money.
Manuscript unaccompanied by proof sheets is subject to the letter rate.
Third-class matter must admit of easy inspection, otherwise it will be charged letter rate on delivery. It must be fully prepaid, or it will not be despatched. New postage must be prepaid for forwarding to a new address or returning to senders.
The limit of weight is four pounds, except single books in separate packages, on which the weight is not limited. It is entitled, like matter of the other classes, to special delivery when special delivery stamps are affixed in addition to the regular postage, or when ten cents in ordinary stamps are affixed in addition to the regular postage and the words "Special Delivery" are placed on the wrapper.
Upon matter of the third class, or upon the wrapper or envelope inclosing the same, or the tag or label attached thereto, the sender may write his own name, occupation, and residence or business address, preceded by the word "from," and may make marks other than by written words to call attention to any word or passage in the text, and may correct any typographical errors. There may be placed upon the blank leaves or cover of any book, or printed matter of the third class, a simple manuscript dedication or inscription not of the nature of a personal correspondence. Upon the wrapper or envelope of third-class matter, or the tag or label attached thereto, may be placed in writing or otherwise the words " Please do not open until Christmas" or words to that effect, and there may be printed any matter mailable as third class. Written designation of the contents such as book, photo," printed matter," is also permissible, but there must be left on the address side a space sufficient for a legible address, postmark and the necessary stamps. Fourth-Class Matter-See Domestic Parcel Post."
Third or Fourth Class Matter Mailable Without Stamps-Under special permits postage may be paid in money for third or fourth class matter mailed in quantities of 2,000 or more identical pieces. For information concerning the regulations governing such mailings inquiry should be made of the postmaster.
Registration-All domestic mail matter except fourth-class matter may be registered at the rate of ten cents for each package in addition to the regular rates of postage, to be fully prepaid by stamps. Each package must bear the name and address of the sender, and a receipt will be returned from the person to whom addressed, when indorsed receipt desired,' or words of similar import. Mail matter can be registered at all post-offices in the United States.
An indemnity-not to exceed $50 for any one registered piece, or the actual value of the piece, if it is less than $50-shall be paid for the loss of first-class registered matter mailed at and addressed to
a United States post-office, and an indemnity not to exceed $25 is paid for domestic third and
For sums not exceeding $2.50, 3 cents; over $2.50 to $5. 5 cents; over $5 to $10, 8 cents; over $10 to $20, 10 cents; over $20 to $30, 12 cents; over $30 to $40, 15 cents; over $40 to $50, 18 cents; Over $50 to $60, 20 cents; over $60 to $75, 25 cents; over $75 to $100, 30 cents.
Stamped Envelopes-Embossed stamped envelopes and newspaper wrappers of several denominations, sizes and colors are kept on sale at post-offices, singly or in quantities, at a small advance on the postage rate. Stamps cut from stamped envelopes are valueless, but postmasters are authorized to give good stamps for stamped envelopes or newspaper wrappers that may be spoiled in directing, if presented in a substantially whole condition.
Unmailable Matter-See also Domestic Parcel Post." -Unmailable domestic matter-that is, matter which is not admissible to the United States mails for delivery in the United States or in any of its possessions-includes:
All matter illegibly, incorrectly, or insufficiently addressed.
All second-class matter and all matter of the third or fourth class not wholly prepaid; and letters and other first-class matter not prepaid one full rate-2 cents. All matter weighing over four pounds, except second-class matter, fourth-class matter. (parcel post), single books, official matter emanating from the Executive Departments and documents printed and circulated by authority of Congress.
Postal, post, or other cards mailed uninclosed which bear delineations, epithets, terms, or language of an indecent, lewd, lascivious, obscene, libelous, scurrilous, defamatory or threatening character, or calculated by the terms or manner or style of display, and obviously intended to reflect injuriously upon the character or conduct of another, also articles bearing such matter upon the wrapper or outside cover. Dunning postal or post cards are included in this class.
Post cards, bearing particles of glass, metal, mica, sand, tinsel, or other similar substances, are unmailable, except as provided under First-Class Matter." All matter concerning any lottery, gift, enterprise, or similar scheme, offering prizes dependent In whole or in part upon lot or chance, or concerning schemes devised for the purpose of obtaining money or property under false pretenses.
Applications for the establishment of post-offices should be addressed to the First Assistant Postmaster-General, accompanied by a statement of the necessity therefor. Instructions will then be given and blauks furnished to enable the petitioners to provide the department with the necessary information.
The franking privilege was abolished July 1, 1873, but the following mail matter may be sent free by legislative saving clauses, viz.:
1. All public documents printed by order of Congress, the Congressional Record and speeches contained therein, franked by Members of Congress, or the Secretary of the Senate, or Clerk of the House. 2. Seeds transmitted by the Secretary of Agriculture, or by any Member of Congress, procured from that Department.
3. Letters and packages relating exclusively to the business of the Government of the United States, mailed only by officers of the same, and letters and parcels mailed by the Smithsonian Institution. All these must be covered by specially printed "penalty" envelopes or labels.
4. The Vice-President, Members and Members-elect and Delegates and Delegates-elect to Congress may frank any mail matter to any Government official or to any person correspondence, not over four ounces in weight, upon official or departmental business.
All communications to Government officers and to Members of Congress are required to be prepaid by stamps unless inclosed in penalty" envelopes furnished for replies.
Suggestions to the Public-Mail all letters, etc.. as early as practicable, especially when sent in large numbers, as is frequently the case with newspapers and circulars.
All mail matter at large post-offices is necessarily handled in great haste and should therefore in all cases be so PLAINLY addressed as to leave NO ROOM FOR DOUBT AND NO EXCUSE FOR ERROR on the part of postal employes. Names of States should be written in full (or their abbreviations very distinctly written) in order to prevent errors which arise from the similarity of such abbreviations as Cal., Col.; Pa., Va., Vt.; Me., Mo., Md. Ioa., Ind.; N. H., N. M., N. Y., N. J., N. C., D. C.; Miss., Minn., Mass.; Nev., Neb.; Penn., Tenn., etc., when hastily or carelessly written. This is especially necessary in addressing mail matter to places of which the names are borne by several post-offices in different States.
Avold as much as possible using envelopes made of flimsy paper, especially where more than one sheet of paper, or any other article than paper, is inclosed. Being often handled, and even in the mailbags subject to pressure, such envelopes not infrequently split open, giving cause of complaint.
Never send money or any other article of value through the mail except either by means of a money order or in a registered letter. Any person who sends money or jewelry in an unregistered letter not only runs a risk of losing his property, but exposes to temptation every one through whose hands his letter passes, and may be the means of ultimately bringing some clerk or letter-carrier to ruiu.
See that every letter or package bears the full name and post-office address of the writer, in order to secure the return of the letter, if the person to whom it is directed cannot be found, portion of the undelivered letters could be returned if the names and addresses of the senders were always fully and plainly written or printed inside or on the envelopes. Persons who have large A much larger correspondence find it most convenient to use "special request envelopes;" but those who only mail an occasional letter can avoid much trouble by writing a request to return if not delivered." etc., on the envelope.
When dropping a letter, newspaper, etc.. Into a street mailing-box, or into the receptacle at a post-office, always see that the packet falls into the box and does not stick in its passage; observe, also, particularly, whether the postage stamps remain securely in their places.
Postage stamps should be placed on the upper right-hand corner of the address side of all mail
The street and number (or box number) should form a part of the address of all mall matter directed to cities. In most cities there are many persons, and even firms, bearing the same name. depositing any package or other article for mailing, the sender should assure himself that it is wrapped and packed in the manner prescribed by postal regulations; that it does not contain unmailable matter Before nor exceed the limit of weight as fixed by law; and that it is fully prepaid and properly addressed.
Domestic Parcel Post."
It is unlawful to send an ordinary letter by express or otherwise outside of the mails unless it be inclosed in a Government-stamped envelope of sufficient value to pay the postage to which it is subject. It is also unlawful to inclose a letter in an express package unless it pertains wholly to the contents of the package.
It is forbidden by the regulations of the Post-Office Department for postmasters to give to any person information concerning the mail matter of another, or to disclose the name of a box-holder at a post-office.
Letters addressed to persons temporarily sojourning in a city where the Free Delivery System is in operation should be marked Transient" or "General Delivery, number or some other designated place of delivery. "if not addressed to a street and
Foreign books, etc., infringing United States copyright are undeliverable if received in foreign mails, or mailed here. The foregoing rates, rules, and suggestions apply to postal matters in the United States.
Domestic Parcel Post.
Fourth-class mail matter embraces all other matter, including farm and factory products, not now embraced by law in either the first, second, or third class, which is not greater in size than seventy-two inches in length and girth combined, nor in form or kind likely to injure the person of any postal employé or damage the mail equipment or other mail matter and not of a character perishable within a period reasonably required for transportation and delivery.
The limit of weight for parcels of fourth-class matter for delivery within the first and second zones is twenty pounds. and second zones is eleven pounds. The limit of weight for parcels intended for delivery in other than the first RATES OF POSTAGE.
Parcels weighing four ounces or less are mailable at the rate of one cent for each ounce or fraction of an ounce, regardless of distance. pound rates shown in the following table, a fraction of a pound being considered a full pound. Parcels weighing more than four ounces are mailable at the The pound rates of postage in the first and second zones are as follows:
2d Zone Rate. 50 to 150
Local Zone Rate.
NOTE-The rate for local delivery applies to all matter mailed at a city carrier office, or at any point within its delivery limits, for delivery by carriers from that office. The rate for local
delivery applies also to all parcels mailed at a post-omce from which a rural route starts, for delivery on such route, or mailed at any point on such route for delivery at any other point thereon, or at the office from which the route starts, or on any rural route starting therefrom, and on all matter mailed at any office for local delivery.
The pound rates of postage for the third, fourth, fifth, sixth, seventh and eighth zones are as follows:
Rate to Alaska, the Hawaiian Islands, the Philippine Islands, Guam, Shanghal (China), Tutulla (Samoa), and the Canal Zone-The rate on parcels for Alaska, the Hawaiian Islands, 1.32 the Philippine Islands, Guam, the United States Postal Agency at Shanghai (China), Tutuila (Samoa). and the Canal Zone (except for parcels weighing four ounces or less, on which the rate is one cent fo each ounce or fraction thereof) is twelve cents for the first pound and twelve cents for each additional pound or fraction thereof.
NOTE-Parcels for the Canal zone, except those having no commercial value, must be accompanied with a Customs Declaration. Rate on Parcels for United States Naval Vessels-The eighth zone rate of postage applies to parcels of fourth-class mail, exceeding four ounces in weight, exchanged between the United States, or any of its possessions, and United States naval vessels stationed in foreign waters. When such
DOMESTIC PARCEL POST-Continued.
vessels are stationed in a port of the United States, or any of its possessions, the rates applicable to or from the post-office at such port shall be charged.
Special Rate for Seeds, Cuttings, Bulbs, Etc.-Seeds, cuttings, bulbs, roots, scions and plants are matter of the fourth class, but are chargeable with the special rate of postage of one cent for each two ounces or fraction thereof, regardless of distance.
Rates for Grain, Vegetables, Etc.-Samples of wheat or other grain in its natural condition, potatoes, beans, peas, chestnuts, acorns, etc., when intended for planting must be prepaid at the special rate of postage prescribed in the preceding paragraph, but when sent for purposes other than planting the parcel post rates apply.
Postage Stamps-Ordinary or parcel post stamps are valid for postage and for insurance and collect on delivery fees on fourth-class mail.
Packages Malled as First-Class Matter Should Be Sealed-When it is desired to send merchandise as first-class matter the packages should be sealed or otherwise closed against inspection, in order to avoid any confusion in the mails as to their proper classification.
Where Parcels Must Be Mailed-Parcels weighing over four ounces must be mailed at a post-office or at a lettered or local named station or branch post-office, or such numbered stations as have been designated to receive parcel post matter. Parcels must bear the name and address of the sender, preceded by the word "From."
Parcels Must Not Be Sealed-Parcels must be prepared for mailing in such manner that the contents can be easily examined. Parcels which are sealed or otherwise closed against inspection, or which contain or bear writing which is not permissible are subject to postage at the first-class (letter) rate and will be treated as first-class matter. If such a parcel exceeds four pounds in weight it is unmailable.
Boxes to which the lids are nailed or screwed may be accepted for mailing at the fourth-class rates of postage, if, with reasonable effort, the lids can be removed for the purpose of permitting examination of the contents.
Parcels in bags or cloth so stitched that the necessary examination can not be made will be regarded as closed against inspection.
Limit of Weight andSize -If a parcel exceeds the limit of weight stated in the tables on preceeding rage, or is greater in size than seventy-two inches in length and girth combined, it must be refused, no matter how small the excess may be in either case.
The law prescribes that a package to be admitted to the parcel post shall not exceed seventytwo inches in combined length and girth. In measuring the length the greatest distance in a straight fine between the two ends of the parcel shall be taken, while the girth is the actual measurement by a tape encircling the parcel at its thickest part.
A parcel not more than 3 feet 6 inches in length may measure as much as 2 feet 6 inches in girth, or around its thickest part. A shorter parcel may be thicker; thus, if it measures no more than 3 feet In length it may measure as much as 3 feet in girth, or around its thickest part. Measurements can berde by means of a six-foot tape line. So much of the tape as is not used in measuring the length is the measure of the maxinun girth permissible.
Permissible Additions and Inclosures-In addition to the name and address of the sender, which is required, it is permissible to write or print on the covering of a parcel, or on a tag or label attached to it, the occupation of the sender, and to indicate in a small space by means of marks, letters, numbers, names or other brief description, the character of the parcel, but ample space must be left on the address side for the full address in legible characters and for the necessary postage stamps. Inscriptions such as "Merry Christmas, "Please do not open until Christmas, Happy New Year," "With best wishes," and the like, may be placed on the covering of the parcel in such manner as not to interfere with the address.
Printed matter relating to an article of merchandise which it accompanies is regarded as descriptive of the article within the meaning of the Postal Laws and Regulations, and therefore is a permissible inclosure with such article when mailed as fourth-class matter.
Printing on an article of merchandise or on its wrapper, or on a label pasted to it in such manner as to form an integral part of it, does not affect the classification of the article as mail matter of the fourth class.
Directions for taking medicine written on a label attached to a bottle or package containing the medicine or inclosed with it are permissible under the provisions of the Postal Laws and Regulations, and do not affect the classification of the parcel.
It is permissible under the provisions of the Postal Laws and Regulations to inclose with matter of the fourth class an invoice showing in writing or printing the name and address of the sender and of the addressee; the names and quantities of articles inclosed, together with inscriptions indieating, "for purpose of description," the price, style, stock number, size and quality of the articles, the order or file number, date of order and date and manner of shipment, the initials or name of the salesman, or of the person by whom the articles were packed or checked.
Third-Class Matter Not Admissible-Articles classified as third-class matter can not be sent by parcel post. Printed books are third-class matter, and postage on them is required to be prepaid at the rate of one cent for each two ounces or fraction of two ounces.
Printed Matter with Samples of Merchandise Attached-Samples of merchandise affixed to circulars or other printed matter will not affect the classification of such matter as third-class mail when the samples occupy less than twenty per cent. of the superficial area of the circulars or other printed matter. When twenty per cent. or more of the space is occupied by samples of merchandise permanently attached thereto, the circulars or other printed matter shall be considered fourth-class mail and chargeable with postage at the rates set forth in the Parcel Post Regulations. Printed catalogues are third-class mail, and postage on them is required to be prepaid at the rate of one cent for each two ounces or fraction of two ounces. Samples of merchandise permanently attached to a catalogue will not affect its classification as third-class mail when such samples constitute only an incidental feature of the catalogue. When less than twenty per cent. of the space in a catalogue is occupied with samples of merchandise, such space will be regarded as an incidental feature, and the third-class rate of postage will apply to the catalogue. When at least twenty per cent. of the space in a catalogue is occupied with samples of merchandise, the catalogue shall be considered fourth-class mail.
Books, Forms, Etc., Partially Printed-Order forms, address tags, report forms, letter and bill heads, insurance and legal forms, post cards, blank check books, receipt books and other books of forms, partially in print, are governed by the classification set forth on pages 7 to 11 of the July 1913, Postal Guide.
Parcels Containing Two or More Classes of Mall Matter-A parcel containing two or more classes of mail matter is chargeable with postage at the rate applicable to the highest class of matter inclosed. A parcel composed of two articles, one being matter of the third class and the other matter of the fourth class, is chargeable with postage at the fourth-class rate when such postage is equal