In writing a book on the Principles of Commerce, my purpose has been to present the theory of commerce in its several important aspects, while yet so emphasizing the relations of the different branches of the subject to each other, as to give unity to the whole. In accordance with this purpose, the book has been written in three Parts (separately paged), viz., (I) The Exchange Mechanism of Commerce; (II) The Economic Advantages of Commerce; and (III) The Transportation Costs of Commerce. Each Part has a real and close connection with the Part immediately preceding or following it; yet no one Part is written merely as an introduction to or appendix to another. Each is important in itself.<br><br>In Part I the aim is to set forth briefly the laws of money and the nature of banking, and then to show, through an analysis of foreign exchange operations, the international nature of the credit relations growing out of trade. In this Part, I have endeavored to analyze, more fully than is usually done, the interrelations of different persons, buyers and sellers, et al., in the credit mechanism of exchange, - to show who are the ultimate creditors when bank checks and bank notes are used in trade and when bills of exchange (especially "long bills") arc used. The flow of money from country to country is explained, and the relation of this flow to fluctuations in the rate of exchange.