The conduct of commercial banking presents problems both to the bankers and to the public, the methods of solution of which will be given attention at this point. The problems concerning the bankers primarily may be grouped under the heads, supply of cash, selection of loans and discounts, and rates; and those which primarily concern the public may be grouped under the heads, protection against unsound practices, and adequacy and economy of service. _1. The Supply of Cash_ The credit balances on checking accounts and the notes of commercial banks are payable on demand in the legal-tender money of the nation to which they belong, and such banks must at all times be prepared to meet these obligations. The term employed to designate the funds provided for this purpose is _reserves_, and in this country they consist of money kept on hand and of credit balances in other banks. In other countries there is also included under this head commercial bills of the kind which can always be discounted. The term _secondary reserve_ is sometimes employed in this country to designate certain securities, such as high-class bonds listed on the stock exchanges, which can be sold readily for cash in case of need. The amount of reserve required can be determined only by experience. In ordinary times it depends chiefly upon the habits of the community in which the bank is located regarding the use of hand-to-hand money as distinguished from checks and upon the character of its customers. These habits differ widely in different nations, and considerably in the different sections and classes of the same nation. In most European and Oriental countries, for example, checks are little used by the masses of the people, while in the United States and England they are widely used. In these latter countries, however, they are less widely used by people in the country than in the cities, and by the laboring than the other classes in the cities. Within the same city one bank may need to keep larger reserves than another on account of the peculiarities of the lines of business carried on by its customers and the classes of people with whom it deals. In times of crisis and other periods of extraordinary demand, bank reserves must be much larger than in ordinary times. Hoarding, unusually large shipments of money to foreign countries and between different sections of the same country, and payments of unusual magnitude, increase the demands for cash made upon banks at such times. The manner in which clearing and other balances between banks are met also has an influence on the amount of reserves required. If such balances are paid daily and always in cash, the amount needed for this purpose is much larger than if they are paid in checks on some one or a few institutions and at longer intervals.