Copper Shortage To Bring LayoffWATERBURY, Conn., Aug. 7—(AP—Irregularities in the delivery of copper will cause the layoff tomorrow of 300 employees of a unit of the Scoville Manufacturing Company's north rolling mill—the second in two weeks.Workers can return to their jobs Monday, Alan C. Curtiss, assistant to the president, asserted.Curtiss noted increased receipts! of copper with improved delivery over July schedules, but said the volume niakes the company operate on a “hand to mouth” basis.The Scoville company employs 5,000.