criticized it for not taxing partnerships, and Congress narrowed the scope of the tax to just sugar and oil companies. The act also authorized the U.S. Treasury to issue $200 million in war bonds at 3 percent interest, provided that no more than $100 million in bonds were outstanding at any time. The government was also permitted to issue up to $100 million in bonds with a maturity of less than a year. This proved "a turning point" in the federal government's ability to create flexible financial instruments critical to maintaining the credit of the United States. There was concern that the Treasury could not find enough buyers for these bonds at such a low interest rate. But there were more than 230,000 buyers of bonds at amounts less than $500 and another 88,000 buyers of bonds at larger amounts. These bond sales and tax revenues generated budget surpluses that lasted through 1917. Issuance of silver coinage continued until passage of the Gold Standard Act of March 14, 1900. The estate tax An estate tax was included in the War Revenue Act. This was not the first estate tax enacted in the history of the United States, but its graduated nature made it the precursor to the modern federal estate tax. The estate tax was strongly opposed, but was never removed from the War Revenue Act. The 1898 tax was levied on estates themselves, not on beneficiaries. The tax varied from 0.75 percent to 15 percent, depending on the size of the estate and the relationship between decedent and legatee. Only personal property was subject to taxation, and the first $10,000 of the estate as well as property transferred from husband to surviving wife were exempted. Supreme Court decisions The U.S. Supreme Court twice ruled on the provisions of the War Revenue Act. In Nicol v. Ames, 173 U.S. 509 (1899) the Supreme Court held that the War Revenue Act's tax on stocks, bonds, securities, and commodities agreements was not a property tax, but was instead a tax on the right to exchange. Thus, the tax was more in the nature of an excise tax. The court also upheld the Act's applicability to livestock sales. In the second case, the constitutionality of the estate tax was in question. The tax was upheld by the Supreme Court in Knowlton v. Moore, 178 U.S. 41 (1900). See also Timeline of the Spanish–American