WELLESLEY HILLS, Ma. (Nov 13)—American Biltrite Inc. reported a rise in net earnings for the third quarter ended Sept. 30. For the period, earnings stood at $3 million, or 88 cents per share on sales of $112 million, the company said. This compares to earnings of $2.8 million, or 79 cents per share on sales of $106 million, during the same period of 1999. American Biltrite CEO and Chairman of the Board Roger S. Marcus said that third-quarter earnings showed improvement over the prior year at all company operations. Quarterly sales also were higher than year-earlier levels at all operations except Congoleum Corp., a 54-percent owned subsidiary. Congoleum´s quarterly sales dipped slightly due to weakness in the manufactured housing industry, American Biltrite said, but an improved sales mix and expense reductions for the unit enabled it to show improved profitability over 1999.