[Illustration: Transferring Mails from an Ocean Greyhound to the Post-office Boat, Postmaster General, through the Chutes.]
Only through these exchange offices can correspondence go from one country to another, as no other offices are provided with the clerical force and system necessary to the handling of international mails. It is at times difficult to explain to business people that a North German Lloyd steamer calling at Gibraltar and Naples will carry mail for Naples only, and that a letter addressed to Gibraltar by that particular steamer cannot be delivered at that port, but will be carried all the way to Naples, whence it will be re-despatched to Gibraltar through a more or less circuitous route. This is because Gibraltar is not an "exchange office" with New York, and "closed mails" are not sent thereto from New York. A "closed mail," as the name indicates, is a mail duly tied up, sealed, and labelled with the name of the exchange office to which it is sent, and not to be opened until it gets there, passing sometimes through four or five countries before reaching its destination. No other kind of mails is carried by steamers, yet the answer will often be made to inquiries, that a certain letter would have been sent "in open mail" to London or elsewhere. This does not mean that the mail in which the letter in question would be sent is despatched "opened," but that it is sent in the "closed" mail for London, there to be opened and disposed of by the London clerks, just as if it had been mailed in London. This course is followed with all correspondence for offices abroad, or even entire countries, which is not in sufficient quantity to justify the establishment of an exchange; and the mails for these offices or countries is sent to the foreign exchange office with the best facilities for disposing of it. Thus mail for Liberia will be sent sometimes to Hamburg, Germany, and at other times to Liverpool, England.
[Illustration: On Board the Postmaster General, at the End of the Chute--Receiving, Piling, and Checking Off Sacks.]
[Illustration: Some Sample Labels from Abroad.
Belgian label--string made fast through wooden block with wax seal and a second block of compressed lead. Paraguay label--plain linen. Austrian label--wooden block, string sealed with wax. German white leather label. Argentine label--strong, ordinary leather. Norwegian label--cardboard--string sealed on back with wax.]