2.—Articles of every kind enclosed in these mails must consist exclusively of those addressed to or sent by the officers and crews of the vessels for which the mails are destined or from which they are dispatched; the rates and conditions of dispatch applicable to them are determined by the Postal Administration of the country to which the vessels belong, in accordance with its domestic regulations.
3.—Unless there be a contrary arrangement between the Offices interested, the Post Office which dispatches or receives the mails in question is accountable to the intermediary Offices for the transit expenses calculated in conformity with the provisions of Article 4.
Article 16
1.—Circulation shall not be given to commercial papers, samples and prints which do not fulfill the conditions prescribed for articles of these categories by Article 5 of the present Convention and by the Regulations for its execution provided for in Article 20.
2.—If any of these articles be given circulation, they are sent back to the office of origin, and, if possible, returned to the sender.
3.—It is forbidden:
1st to send by mail:
- a) samples and other articles which, from their nature, may prove dangerous to the postal employés, soil or injure the correspondence;
- b) explosive, inflammable or dangerous substances; animals and insects, living or dead, excepting the cases provided for in the detailed Regulations.
2nd to insert in ordinary or registered articles placed in the mails:
- a) current coin;
- b) articles liable to customs duty;
- c) gold or silver bullion, precious stones, jewelry, and other precious articles, but only in case their insertion or transmission is prohibited by the legislation of the countries concerned.
4.—Articles coming under the prohibition of section 3 preceding which have been forwarded erroneously, should be returned to the office of origin, except in cases where the Administration of the country of destination is authorized by its legislation or by its domestic regulations to dispose of them otherwise.
Explosive, inflammable or dangerous substances, however, are not returned to the office of origin; they are destroyed on the spot under the direction of the Administration which detects their presence.
5.—There is, moreover, reserved to the Government of every country of the Union the right to refuse to convey over its territory, or to deliver, as well articles liable to the reduced rate in regard to which the laws, ordinances
