These are specimen prints of six bond issues by New Orleans Public Service Inc. (NOPSI), in 1922, 1925, 1944, 1948, 1953, and 1966, each issue to mature in 30 years (1952, 1955, 1974, 1978, 1983, and 1996).  There are two 1944 certificates, one with a face value of $1.5 million dollars, the other a face value of $3 million dollars!  The 1966 certificate was printed by the Security Banknote Co., the others by the American Bank Note Co. of New York.  Note how the ornate scroll work of the border, typical of this type of document, became simplified as tastes changed over the years.  (Cox does not catalog NOPSI stocks or bonds.)