Investors yanked money out of stocks Thursday after new reports from the U.S. and China pointed to a sharp slowdown in manufacturing. The Dow Jones industrial plunged 251 points, the second-biggest drop this year. Losses in energy and materials companies led a widespread rout on the stock market. The Dow started sinking after 10 a.m., when the Philadelphia branch of the Federal Reserve reported a sharp contraction in manufacturing in the Northeast. The losses accelerated throughout the day.