The Chinese government had hired Patton Boggs LLP, the biggest Washington lobby firm, to give it advice about Congress, according to a federal disclosure. The Chinese embassy in Washington will pay Patton Boggs $22,000 a month, according to contract papers filed with the U.S. Justice Department. China hired Patton Boggs in July, before congressional pressure helped scuttle an $18.5 billion bid by Beijing-based CNOOC Ltd., an oil producer, to buy Unocal Corp. of El Segundo, Calif. Mark Cowan, Robert Horn and Timothy Chorba, a former U.S. ambassador to Singapore, will lead Patton Boggs' work with the embassy. Cowan is a...