Pennsylvania Statutes Title 72 P.S. Taxation and Fiscal Affairs § 3621. How constituted

The sinking-fund shall consist of the proceeds of the sale of the public works, or any part thereof, income from or proceeds of the sale of any stocks owned by the Commonwealth, and moneys appropriated to said sinking-fund by the General Assembly from time to time and accumulations thereon:  Provided, That this act shall not be so construed as to authorize the use or application of any paid into the sinking-fund otherwise than in the extinguishment of the public debt, unless in case of war, invasion or insurrection.