Summary

Franklin Escher Elements of Foreign Exchange: A Foreign Exchange Primer

What the foreign exchange business really is grounded on is the existence of commercial bills called into existence by exports of merchandise.
There are houses doing an extensive exchange business who never buy commercial long bills, but the operations they carry on are made possible only by the fact that most other houses do. A foreign exchange department which does not handle this kind of exchange is necessarily on the "outside" of the real business—‌is like a bond broker who does not carry bonds with his own money but merely trades in and out on other people's operations.
Source: Gutenberg

Franklin Escher Elements of Foreign Exchange: A Foreign Exchange Primer

For whether the banker sends over in every mail a bewildering assortment of every conceivable form of foreign exchange to be credited to his account abroad, or whether he confines himself to remittances of the simplest kinds of bills, the idea remains exactly the same—‌he is depositing money to the credit of his account in order that he may have a balance on which he can draw.
Source: Gutenberg

Franklin Escher Elements of Foreign Exchange: A Foreign Exchange Primer

In the case of a "payment" bill, the credit of the man on whom it is drawn is not good enough to entitle him to such a privilege, and the only way he can get actual possession of the goods is to actually pay the draft under a rebate-of-interest arrangement. All bills drawn on banks are naturally "acceptance" bills; and being discountable and thus immediately convertible into cash abroad, command a better rate of exchange in the New York market than "payment" bills, which may be allowed to run all the way to maturity before a single pound sterling is paid on them.
Source: Gutenberg

Get perspective with Kwize: daily news enlightened by great literature