Government, and comprises revenue fu nds proper, depositary, and trust funds. "Revenue funds" comprise all Government funds derived from the income of the Government in any of its branches and available for appropriation or expenditure according to law. "Trust funds" are Government funds which have officially come into the possession of the Government or of a Government officer as trustee, agent, or administrator, or which have been received as a guaranty for the fulfillment of some obligation. A trust fu nd is available only for the specific purpose for which it was created or for which it came into the possession of the Government. THEcAS "Depositary funds" are Government funds over which the officer accountable therefor may retain control for the lawful purposes for which the same came into his possession, being subject to his official check for such purposes. The term embraces moneys in t he Insular Treasury in its capacity as a depositary and all Government moneys in depositary banks. "Depositary" means any institution lawfully authorized to receive Government moneys upon current or time deposit. The Insular Treasury, in addition to its faculty as Treasury of the Philippine Islands, for the keeping of treasury and trust funds, is also t he chief depositary. "Contract" includes every species of engagement or agreement competent to originate legal liability or to serve as the basis of a civil action between private parties. SECTION  630 . Use of Appropriated Funds.  — All moneys appropriated for the various branches of the public service shall be available solely for the specific purposes for which appropriated, and for no others. Moneys appropriated for salaries and wages shall  not be available for contingent expenses or  vice versa. [148-1; 2319-3.] SECTION  631 . Appropriations Not Confined to Fiscal Year.  — In the absence of express provision, legislative appropriations shall not be confined to fiscal years, but shall be available until expended for the purposes for which appropriated, subject to such  restrictions as may be specifically imposed by law; but the net surplus of all annual appropriations for the current expenses of the Government remaining at the end of the fiscal year for which such appropriations 198 Copyright 2012 CD Technologies Asia, Inc. and Accesslaw, Inc. Philippine Law Encyclopedia 2011 ARTICLE  IV Application of Appropriated Funds