Mr. Merriam was as well-known for the projects he didn't build as for the many successful ones he did. His most ambitious project - and his most glorious failure - was the domed stadium, trade center and hotel complex at Penn's Landing. He envisioned the project in the mid-1960s when the city was struggling to build a new stadium to replace the aging Connie Mack Stadium.
Ultimately, his $250 million dream went up in smoke when voters approved a bond issue to build Veterans Stadium after a battle that raged for six months.
But because Mr. Merriam was always seeking new adventures, that wasn't the only one of his promising projects that never got done.
Another was the plan to turn part of the Curtis Building at Sixth and Walnuts Streets, which he then owned, into a museum of American painting and sculpture with works borrowed from other museums.
Proposed with much fanfare, the plan was quietly rejected by the Museum of Art and the Pennsylvania Academy of the Fine Arts, then died.
Those failures were more than balanced by a string of successful developments that made Mr. Merriam a very wealthy man.
He made millions, for example, as one of three major figures who took an enormous risk to develop the Oxford Valley Mall in Bucks County.
Howard Shaeffer, of Kravco, who developed the mall, said Mr. Merriam was ''the toughest businessman I've ever dealt with. He's the last of the old- time risk-takers."
Mayor Rendell, who met Mr. Merriam during his 1986 campaign for governor, praised him yesterday for his philanthropy and decency. "His good heart knew no bounds," said Rendell, who said Mr. Merriam had sent him "a $10,000 check out of the blue after hearing me speak" and later backed him with tens of thousands more.
"In the eight years since, he's never asked me for one favor. Not even a parking spot. It's extraordinary," Rendell said.
Mr. Merriam's toughness was hidden under a velvet surface. Those who watched him in action described him as relaxed and low-key, with a calm voice and slow, articulate manner more suggestive of an English teacher than a businessman. He was a small, dapper man, with a liking for cigars and a reputation for never turning away from a good scrap.
Montgomery County officials knew how tough Mr. Merriam could be.
For example, he argued in 1982 that tax assessments on his Cedarbrook Hill apartments were too high. He paid under protest, but the money went into escrow rather than into municipal budgets while the case wound its way through the courts.
In January 1993, the state Supreme Court settled the matter in Mr. Merriam's favor. It was a big loss for the township, and a million-dollar victory for Mr. Merriam.
When he lost out on a $52 million contract to provide federal offices in his Curtis Building to a bidder with strong political ties to Sen. Hugh Scott and the Nixon administration, he fought the agreement in court and received a settlement - reported to be $1.5 million - to drop the suit.
Mr. Merriam was born in Chicago. He studied at the University of Pennsylvania's Wharton School, receiving a bachelor's degree in 1931 and a master's degree the following year.
While there, he captained the water polo team and made all-American for three years. He also was a member of the golf and swimming teams.
His real-estate career began in Philadelphia in the 1930s with Joseph F. and Reynold H. Greenberg, for whom he bought, sold and developed office, retail and commercial properties.
In 1934, he helped set up the Federal Housing Association, which provided financing for large and small housing projects. He also worked with A&P, developing models for suburban supermarkets.
His first success as a developer was in the 1930s with Jericho Manor, a 137-unit garden apartment project in Jenkintown. In 1953, he developed the 220-unit Thomas Wynne apartments in Wynnewood.
He is best-known as the developer of the Cedarbrook Hill apartments, a 985- unit high-rise complex in Wyncote, and of the Cedarbrook Mall, the first enclosed shopping center in eastern Pennsylvania.
For 40 years, he owned and managed the Buffalo Weaving & Belting Co.
During World War II, he helped train Navy frogmen in underwater maneuvers, and, during the Korean conflict, he designed and manufactured the coffins in which bodies of dead U.S. soldiers were returned home.
Mr. Merriam lived at Maybrook House, a 35-room castle in a 55-acre woods off Penn Road in Wynnewood.
He was a member of the board of the Pennsylvania Academy of the Fine Arts and a member of the Franklin Institute, the Wynnewood Civic Association, the National Republican Club, the Art Alliance and the Art Museum.
He is survived by his second wife, Elizabeth C. Lockyer Merriam.
A memorial service will be held at 10:30 a.m. Tuesday at St. Paul's Episcopal Church, York and Ashbourne Roads, Elkins Park.