In the application of these means the methods employed by the various groups of institutions mentioned differ widely and they are efficient in different degrees, partly because they have other objects in view besides the promotion of saving and partly because they deal with different classes of people. Savings banks constitute the only group to which the term bank can properly be applied and consequently the only one to which attention will here be given. In a book entitled, _Savings and Savings Institutions_, written by Professor Hamilton of Syracuse University, the following definition is given:[Pages 161 and 162.] Savings banks are institutions established by public authority, or by private persons, in order to encourage habits of saving by affording special security to owners of deposits, and by the payment of interest to the full extent of the net earnings, less whatever reserve the management may deem expedient for a safety fund; and in furtherance of this purpose bank offices are located at places where they are calculated to encourage savings among those persons who most need such encouragement. Professor Hamilton classifies these institutions as trustee, cooperative, municipal, and postal savings banks. In the first group he places institutions managed by boards of philanthropically inclined persons who serve without pay; in the second, those managed cooperatively by the people who make use of them; in the third, those established and administered by municipalities; and in the fourth, those connected with the post-office departments of governments. The strength of trustee savings banks lies in the comparatively low costs of their administration and in the fact that in their investments they are likely to enjoy the advantages of the judgment and enthusiasm of people skilled in the investment business; that of cooperative savings banks, in their adaptability to the special needs of their constituents and in the education which cooperative administration involves; and that of municipal, and especially of postal savings banks, in their capacity to place their services within the easy reach of all who need them and in the confidence which their public character inspires. In the investment of the funds intrusted to savings banks, safety and as large returns as are consistent with it, rather than ease of liquidation, are the prime considerations, and hence they usually take the form of high grade investment securities rather than of commercial paper. Their deposits are usually subject to withdrawal only after due notice, and, being savings deposits, their withdrawal usually follows only after the lapse of a considerable period of time. The purpose of their withdrawal is frequently investment and this is sometimes made through the agency of the bank which held the deposit and may involve merely a transfer of securities.