THOMAS A. EDISON An interesting Edison D.S., a stock certificate issued to Edison for one hundred shares in The Edison Portland Cement Company, June 14, 1899, boldly signed "Thomas A. Edison " on verso. Edison's bold black signature has been lightly canceled with a red pen, else fine condition. Edison Portland cement was used extensively for buildings, roads, dams, and other structures, including Yankee Stadium. Edison also designed a system for building inexpensive cement houses that he planned to license to other manufacturers, though only a few of these were ever built. $800-1,200