By The Associated PressCorn prices are falling sharply, continuing a seesaw week. Corn for December delivery dropped 18.75 cents, or 3.9 percent, to $4.65 a bushel Thursday. The price has bounced around this week, as forecasts for dry weather in the Midwest counter predictions that this year's corn harvest will rebound after last year's drought. In trading of other agricultural products, soybeans and wheat also dropped more than 1 percent. Metals were higher. Copper for September delivery rose 2.3 cents to $3.33 a pound. Silver for the same month gained 7.2 cents to $23.04 an ounce. Gold for December rose 70 cents to $1,370.80 an ounce.