The exception in energy commodities was natural gas, which gained 7 cents to $3.53 per 1,000 cubic feet. Other energy commodities fell. Wholesale gasoline fell 3 cents to $3.10 a gallon. Heating oil slipped 1 cent to $2.92 a gallon.Gold, silver and copper were virtually flat. Gold for April delivery rose 10 cents to $1,572.40 per ounce. May silver edged up less than 1 cent to $28.496 per ounce. May copper inched up less than 1 cent to $3.5015 per pound.