Forward thinking.(FROM THE CASTLE)

S. DILLON RIPLEY, Secretary of the Smithsonian from 1964 to 1984, created eight new museums, a Folklife Festival on the National Mall--and, 40 years ago, this magazine. Today, as we look forward to the next 40 years, we believe we are entering another era of expansion--particularly on the Web. Last year there were 30 million visits to Smithsonian museums, but there were more than six times that number to our Web sites. With an estimated 1.7 billion Web users in a global population of 6.8 billion, the Smithsonian's digital future is only beginning. Imagine a world where our 136.9 million artifacts, specimens and works of art are captured in stunning 3-D digital images that virtual …