''Smithsonian World'' is not a scientific ''Ripley's Believe It or Not.'' A superficial glance may fool some viewers into believing so. But there's actually a special joy in the intellectual shock of recognition that stems from the expert linkage of specialized information in this four-part series. Now the final edition, Designs for Living (Wednesday, 8-9 p.m., check local listings for premiere and repeats), offers a fascinating mix of information and entertainment combined with a smattering of historical nostalgia.
The journey begins with a first-time visit to the Independence, Mo., home of President Harry S. Truman, stopping off for a peek back into the history of the 1948 election in which Truman unexpectedly trounced Thomas E. Dewey.
Smithsonian host David McCullough, a remarkably empathetic listener, is given a gracious tour of the Trumans' General Grant Gothic 19th-century house by the only surviving member of the family, daughter Margaret.
Margaret points out that her mother had a much greater influence on the decisions of the President than most people realized. What would she like people to remember about her parents? ''Their warm relationship with one another.''
Writer/historian McCullough, who has proven to be an American version of Alistair Cooke, then proceeds to take viewers on a Smithsonian tour of skyscrapers (''New York's skyline is the greatest man-made spectacle on earth'') , an inside look at astronaut spacesuits, and an astounding if slightly incomprehensible visit to the bottom of a salt mine where scientists are trying to observe the decay of a proton.
''Designs for Living'' continues the first-season tradition of excellence for ''Smithsonian World.'' From the very start, this new series, co-produced by WETA/Washington and the Smithsonian Institution on a grant from the James S. McDonnell Foundation, has skillfully mustered many of the far-reaching facilities of the Smithsonian and placed them in a stimulating and entertaining framework.