10.--6. Cause to be prepared and distributed postage and registration stamps necessary for the prepayment of postages and registration charges, under this Act; also stamped envelopes for the like purpose and post-cards and stamped post bands or wrappers for newspapers or other mailable articles not being post letters. 19. [_Letter rate of 3 cents per 1/2 oz._]: and such postage rate of three cents shall be pre-paid by postage stamp or stamps at the time of posting the letter, otherwise such letter shall not be forwarded by post, except that letters addressed to any place in Canada and on which one full rate of three cents has been so pre-paid, shall be forwarded to their destination charged with double the amount of the postage thereon not so prepaid, which amount shall be collected on delivery. 20. [_Drop letter rate restricted to_ "one cent per half ounce weight."] 22. The rate of postage on newspaper and periodical publications printed and published in Canada, and issued not less frequently than once a month from a known office of publication or news agency, and addressed and posted by and from the same to regular subscribers or news agents, shall be one cent for each pound weight, or any fraction of a pound weight, to be prepaid by postage stamps or otherwise as the Postmaster General may, from time to time, direct; and such newspapers and periodicals shall be put into packages and delivered into the post office, and the postage rate thereon prepaid by the sender thereof, under such regulations as the Postmaster General may, from time to time, direct. 23. Newspapers and periodicals weighing less than one ounce each may be posted singly at a postage rate of half a cent each, which must be in all cases prepaid by postage stamp affixed to each. 24. On all newspapers and periodicals posted in Canada, except in the cases hereinbefore expressly provided for, and on books, etc., etc., [_repeats Sec. 26 of Act of 1867_], the rate of postage shall be one cent for each four ounces or fraction of four ounces, ... and this postage rate shall be prepaid by postage stamps or stamped post bands or wrappers.... 27. [_Repeats Sec. 29 of Act of 1867_] And when any letter or other mailable matter is posted in Canada without prepayment, or insufficiently prepaid, in any case in which prepayment is by this Act made obligatory, the Postmaster General may detain the same, and cause it to be returned, when practicable, to the sender.